feat: add utils from isolex

.gitlab-ci.yml

@@ -150,7 +150,7 @@ sonar-success:
   script:
     - make node_modules
     - sonar-scanner
-        -Dsonar.projectKey=ssube_rollup-template
+        -Dsonar.projectKey=ssube_js-utils
         -Dsonar.projectVersion=${CI_COMMIT_REF_SLUG}
         -Dsonar.organization=ssube-github
         -Dsonar.sources=src/,test/

config/eslint.json

@@ -154,7 +154,6 @@
             "error",
             "any",
             "Number",
-            "String",
             "Boolean",
             "Undefined"
         ],

config/rollup-named.json

@@ -2,5 +2,11 @@
   "node_modules/chai/index.js": [
     "expect",
     "use"
+  ],
+  "node_modules/lodash/lodash.js": [
+    "isFunction",
+    "isMap",
+    "isObject",
+    "isString"
   ]
 }

docs/api/index.md

@@ -8,5 +8,5 @@
 
 |  Package | Description |
 |  --- | --- |
-|  [@apextoaster/rollup-template](./rollup-template.md) |  |
+|  [@apextoaster/js-utils](./js-utils.md) |  |
 

docs/api/js-utils.arraymapper._constructor_.md

@@ -0,0 +1,20 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ArrayMapper](./js-utils.arraymapper.md) &gt; [(constructor)](./js-utils.arraymapper._constructor_.md)
+
+## ArrayMapper.(constructor)
+
+Constructs a new instance of the `ArrayMapper` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(options: ArrayMapperOptions);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  options | <code>ArrayMapperOptions</code> |  |
+

docs/api/js-utils.arraymapper.map.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ArrayMapper](./js-utils.arraymapper.md) &gt; [map](./js-utils.arraymapper.map.md)
+
+## ArrayMapper.map() method
+
+<b>Signature:</b>
+
+```typescript
+map(input: Array<string>): Map<string, Array<string>>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  input | <code>Array&lt;string&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Map<string, Array<string>>`
+

docs/api/js-utils.arraymapper.md

@@ -0,0 +1,32 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ArrayMapper](./js-utils.arraymapper.md)
+
+## ArrayMapper class
+
+<b>Signature:</b>
+
+```typescript
+export declare class ArrayMapper 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(options)](./js-utils.arraymapper._constructor_.md) |  | Constructs a new instance of the <code>ArrayMapper</code> class |
+
+## Properties
+
+|  Property | Modifiers | Type | Description |
+|  --- | --- | --- | --- |
+|  [rest](./js-utils.arraymapper.rest.md) |  | <code>string</code> |  |
+|  [skip](./js-utils.arraymapper.skip.md) |  | <code>number</code> |  |
+|  [take](./js-utils.arraymapper.take.md) |  | <code>Array&lt;string&gt;</code> |  |
+
+## Methods
+
+|  Method | Modifiers | Description |
+|  --- | --- | --- |
+|  [map(input)](./js-utils.arraymapper.map.md) |  |  |
+

docs/api/js-utils.arraymapper.rest.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ArrayMapper](./js-utils.arraymapper.md) &gt; [rest](./js-utils.arraymapper.rest.md)
+
+## ArrayMapper.rest property
+
+<b>Signature:</b>
+
+```typescript
+readonly rest: string;
+```

docs/api/js-utils.arraymapper.skip.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ArrayMapper](./js-utils.arraymapper.md) &gt; [skip](./js-utils.arraymapper.skip.md)
+
+## ArrayMapper.skip property
+
+<b>Signature:</b>
+
+```typescript
+readonly skip: number;
+```

docs/api/js-utils.arraymapper.take.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ArrayMapper](./js-utils.arraymapper.md) &gt; [take](./js-utils.arraymapper.take.md)
+
+## ArrayMapper.take property
+
+<b>Signature:</b>
+
+```typescript
+readonly take: Array<string>;
+```

docs/api/js-utils.asynctracker._constructor_.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [(constructor)](./js-utils.asynctracker._constructor_.md)
+
+## AsyncTracker.(constructor)
+
+Constructs a new instance of the `AsyncTracker` class
+
+<b>Signature:</b>
+
+```typescript
+constructor();
+```

docs/api/js-utils.asynctracker.clear.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [clear](./js-utils.asynctracker.clear.md)
+
+## AsyncTracker.clear() method
+
+<b>Signature:</b>
+
+```typescript
+clear(): void;
+```
+<b>Returns:</b>
+
+`void`
+

docs/api/js-utils.asynctracker.disable.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [disable](./js-utils.asynctracker.disable.md)
+
+## AsyncTracker.disable() method
+
+<b>Signature:</b>
+
+```typescript
+disable(): void;
+```
+<b>Returns:</b>
+
+`void`
+

docs/api/js-utils.asynctracker.dump.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [dump](./js-utils.asynctracker.dump.md)
+
+## AsyncTracker.dump() method
+
+<b>Signature:</b>
+
+```typescript
+dump(): void;
+```
+<b>Returns:</b>
+
+`void`
+

docs/api/js-utils.asynctracker.enable.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [enable](./js-utils.asynctracker.enable.md)
+
+## AsyncTracker.enable() method
+
+<b>Signature:</b>
+
+```typescript
+enable(): void;
+```
+<b>Returns:</b>
+
+`void`
+

docs/api/js-utils.asynctracker.getstack.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [getStack](./js-utils.asynctracker.getstack.md)
+
+## AsyncTracker.getStack() method
+
+<b>Signature:</b>
+
+```typescript
+static getStack(): string;
+```
+<b>Returns:</b>
+
+`string`
+

docs/api/js-utils.asynctracker.md

@@ -0,0 +1,38 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md)
+
+## AsyncTracker class
+
+Async resource tracker using node's internal hooks.
+
+This probably won't work in a browser. It does not hold references to the resource, to avoid leaks. Adapted from https://gist.github.com/boneskull/7fe75b63d613fa940db7ec990a5f5843\#file-async-dump-js
+
+<b>Signature:</b>
+
+```typescript
+export declare class AsyncTracker 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)()](./js-utils.asynctracker._constructor_.md) |  | Constructs a new instance of the <code>AsyncTracker</code> class |
+
+## Properties
+
+|  Property | Modifiers | Type | Description |
+|  --- | --- | --- | --- |
+|  [size](./js-utils.asynctracker.size.md) |  | <code>number</code> |  |
+
+## Methods
+
+|  Method | Modifiers | Description |
+|  --- | --- | --- |
+|  [clear()](./js-utils.asynctracker.clear.md) |  |  |
+|  [disable()](./js-utils.asynctracker.disable.md) |  |  |
+|  [dump()](./js-utils.asynctracker.dump.md) |  |  |
+|  [enable()](./js-utils.asynctracker.enable.md) |  |  |
+|  [getStack()](./js-utils.asynctracker.getstack.md) | <code>static</code> |  |
+

docs/api/js-utils.asynctracker.size.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [AsyncTracker](./js-utils.asynctracker.md) &gt; [size](./js-utils.asynctracker.size.md)
+
+## AsyncTracker.size property
+
+<b>Signature:</b>
+
+```typescript
+get size(): number;
+```

docs/api/js-utils.childprocesserror._constructor_.md

@@ -0,0 +1,21 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ChildProcessError](./js-utils.childprocesserror.md) &gt; [(constructor)](./js-utils.childprocesserror._constructor_.md)
+
+## ChildProcessError.(constructor)
+
+Constructs a new instance of the `ChildProcessError` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(msg?: string, ...nested: Array<Error>);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  msg | <code>string</code> |  |
+|  nested | <code>Array&lt;Error&gt;</code> |  |
+

docs/api/js-utils.childprocesserror.md

@@ -0,0 +1,18 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ChildProcessError](./js-utils.childprocesserror.md)
+
+## ChildProcessError class
+
+<b>Signature:</b>
+
+```typescript
+export declare class ChildProcessError extends BaseError 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(msg, nested)](./js-utils.childprocesserror._constructor_.md) |  | Constructs a new instance of the <code>ChildProcessError</code> class |
+

docs/api/js-utils.concat.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [concat](./js-utils.concat.md)
+
+## concat() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function concat(chunks: Array<Buffer>): Buffer;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  chunks | <code>Array&lt;Buffer&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Buffer`
+

docs/api/js-utils.countof.md

@@ -0,0 +1,26 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [countOf](./js-utils.countof.md)
+
+## countOf() function
+
+Calculate the "length" of an array or value.
+
+Arrays return their length, single values return 1, and nil values return 0. This counts the number of elements that setOrPush would add.
+
+<b>Signature:</b>
+
+```typescript
+export declare function countOf(val: unknown): number;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  val | <code>unknown</code> |  |
+
+<b>Returns:</b>
+
+`number`
+

docs/api/js-utils.defaultwhen.md

@@ -0,0 +1,23 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [defaultWhen](./js-utils.defaultwhen.md)
+
+## defaultWhen() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function defaultWhen<TVal>(condition: boolean, ...items: Array<TVal>): TVal;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  condition | <code>boolean</code> |  |
+|  items | <code>Array&lt;TVal&gt;</code> |  |
+
+<b>Returns:</b>
+
+`TVal`
+

docs/api/js-utils.defer.md

@@ -0,0 +1,25 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [defer](./js-utils.defer.md)
+
+## defer() function
+
+Resolve after a set amount of time.
+
+<b>Signature:</b>
+
+```typescript
+export declare function defer<T = undefined>(ms: number, val?: T): Promise<T>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  ms | <code>number</code> |  |
+|  val | <code>T</code> |  |
+
+<b>Returns:</b>
+
+`Promise<T>`
+

docs/api/js-utils.dict.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [Dict](./js-utils.dict.md)
+
+## Dict interface
+
+<b>Signature:</b>
+
+```typescript
+export interface Dict<TVal> 
+```

docs/api/js-utils.doesexist.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [doesExist](./js-utils.doesexist.md)
+
+## doesExist() function
+
+Check if a variable is not nil.
+
+<b>Signature:</b>
+
+```typescript
+export declare function doesExist<T>(val: Optional<T>): val is T;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  val | <code>Optional&lt;T&gt;</code> |  |
+
+<b>Returns:</b>
+
+`val is T`
+

docs/api/js-utils.encode.md

@@ -0,0 +1,23 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [encode](./js-utils.encode.md)
+
+## encode() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function encode(chunks: Array<Buffer>, encoding: string): string;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  chunks | <code>Array&lt;Buffer&gt;</code> |  |
+|  encoding | <code>string</code> |  |
+
+<b>Returns:</b>
+
+`string`
+

docs/api/js-utils.entriesof.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [entriesOf](./js-utils.entriesof.md)
+
+## entriesOf() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function entriesOf<TVal>(map: Optional<MapLike<TVal>>): Array<[string, TVal]>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  map | <code>Optional&lt;MapLike&lt;TVal&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Array<[string, TVal]>`
+

docs/api/js-utils.externalmodule.data.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ExternalModule](./js-utils.externalmodule.md) &gt; [data](./js-utils.externalmodule.data.md)
+
+## ExternalModule.data property
+
+<b>Signature:</b>
+
+```typescript
+data?: unknown;
+```

docs/api/js-utils.externalmodule.export.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ExternalModule](./js-utils.externalmodule.md) &gt; [export](./js-utils.externalmodule.export.md)
+
+## ExternalModule.export property
+
+<b>Signature:</b>
+
+```typescript
+export: string;
+```

docs/api/js-utils.externalmodule.md

@@ -0,0 +1,20 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ExternalModule](./js-utils.externalmodule.md)
+
+## ExternalModule interface
+
+<b>Signature:</b>
+
+```typescript
+export interface ExternalModule 
+```
+
+## Properties
+
+|  Property | Type | Description |
+|  --- | --- | --- |
+|  [data](./js-utils.externalmodule.data.md) | <code>unknown</code> |  |
+|  [export](./js-utils.externalmodule.export.md) | <code>string</code> |  |
+|  [require](./js-utils.externalmodule.require.md) | <code>string</code> |  |
+

docs/api/js-utils.externalmodule.require.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ExternalModule](./js-utils.externalmodule.md) &gt; [require](./js-utils.externalmodule.require.md)
+
+## ExternalModule.require property
+
+<b>Signature:</b>
+
+```typescript
+require: string;
+```

docs/api/js-utils.filternil.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [filterNil](./js-utils.filternil.md)
+
+## filterNil() function
+
+Remove any null or undefined items from the list.
+
+<b>Signature:</b>
+
+```typescript
+export declare function filterNil<TItem>(list: ArrayLike<Optional<TItem>>): Array<TItem>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  list | <code>ArrayLike&lt;Optional&lt;TItem&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Array<TItem>`
+

docs/api/js-utils.gettestlogger.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [getTestLogger](./js-utils.gettestlogger.md)
+
+## getTestLogger() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function getTestLogger(verbose?: boolean): Logger;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  verbose | <code>boolean</code> |  |
+
+<b>Returns:</b>
+
+`Logger`
+

docs/api/js-utils.invalidargumenterror._constructor_.md

@@ -0,0 +1,21 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [InvalidArgumentError](./js-utils.invalidargumenterror.md) &gt; [(constructor)](./js-utils.invalidargumenterror._constructor_.md)
+
+## InvalidArgumentError.(constructor)
+
+Constructs a new instance of the `InvalidArgumentError` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(msg?: string, ...nested: Array<Error>);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  msg | <code>string</code> |  |
+|  nested | <code>Array&lt;Error&gt;</code> |  |
+

docs/api/js-utils.invalidargumenterror.md

@@ -0,0 +1,18 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [InvalidArgumentError](./js-utils.invalidargumenterror.md)
+
+## InvalidArgumentError class
+
+<b>Signature:</b>
+
+```typescript
+export declare class InvalidArgumentError extends BaseError 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(msg, nested)](./js-utils.invalidargumenterror._constructor_.md) |  | Constructs a new instance of the <code>InvalidArgumentError</code> class |
+

docs/api/js-utils.isdebug.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [isDebug](./js-utils.isdebug.md)
+
+## isDebug() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function isDebug(): boolean;
+```
+<b>Returns:</b>
+
+`boolean`
+

docs/api/js-utils.isnil.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [isNil](./js-utils.isnil.md)
+
+## isNil() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function isNil<T>(val: Optional<T>): val is Nil;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  val | <code>Optional&lt;T&gt;</code> |  |
+
+<b>Returns:</b>
+
+`val is Nil`
+

docs/api/js-utils.makedict.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [makeDict](./js-utils.makedict.md)
+
+## makeDict() function
+
+Turns a map or dict into a dict
+
+<b>Signature:</b>
+
+```typescript
+export declare function makeDict<TVal>(map: Optional<MapLike<TVal>>): Dict<TVal>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  map | <code>Optional&lt;MapLike&lt;TVal&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Dict<TVal>`
+

docs/api/js-utils.makemap.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [makeMap](./js-utils.makemap.md)
+
+## makeMap() function
+
+Clone a map or map-like object into a new map.
+
+<b>Signature:</b>
+
+```typescript
+export declare function makeMap<TVal>(val: Optional<MapLike<TVal>>): Map<string, TVal>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  val | <code>Optional&lt;MapLike&lt;TVal&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Map<string, TVal>`
+

docs/api/js-utils.maplike.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [MapLike](./js-utils.maplike.md)
+
+## MapLike type
+
+A `Map` or dictionary object with string keys and `TVal` values.
+
+<b>Signature:</b>
+
+```typescript
+export declare type MapLike<TVal> = Map<string, TVal> | Dict<TVal>;
+```

docs/api/js-utils.md

@@ -0,0 +1,75 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md)
+
+## js-utils package
+
+## Classes
+
+|  Class | Description |
+|  --- | --- |
+|  [ArrayMapper](./js-utils.arraymapper.md) |  |
+|  [AsyncTracker](./js-utils.asynctracker.md) | Async resource tracker using node's internal hooks.<!-- -->This probably won't work in a browser. It does not hold references to the resource, to avoid leaks. Adapted from https://gist.github.com/boneskull/7fe75b63d613fa940db7ec990a5f5843\#file-async-dump-js |
+|  [ChildProcessError](./js-utils.childprocesserror.md) |  |
+|  [InvalidArgumentError](./js-utils.invalidargumenterror.md) |  |
+|  [MissingKeyError](./js-utils.missingkeyerror.md) |  |
+|  [NotFoundError](./js-utils.notfounderror.md) |  |
+|  [NotImplementedError](./js-utils.notimplementederror.md) |  |
+|  [TimeoutError](./js-utils.timeouterror.md) |  |
+
+## Functions
+
+|  Function | Description |
+|  --- | --- |
+|  [concat(chunks)](./js-utils.concat.md) |  |
+|  [countOf(val)](./js-utils.countof.md) | Calculate the "length" of an array or value.<!-- -->Arrays return their length, single values return 1, and nil values return 0. This counts the number of elements that setOrPush would add. |
+|  [defaultWhen(condition, items)](./js-utils.defaultwhen.md) |  |
+|  [defer(ms, val)](./js-utils.defer.md) | Resolve after a set amount of time. |
+|  [doesExist(val)](./js-utils.doesexist.md) | Check if a variable is not nil. |
+|  [encode(chunks, encoding)](./js-utils.encode.md) |  |
+|  [entriesOf(map)](./js-utils.entriesof.md) |  |
+|  [filterNil(list)](./js-utils.filternil.md) | Remove any null or undefined items from the list. |
+|  [getTestLogger(verbose)](./js-utils.gettestlogger.md) |  |
+|  [isDebug()](./js-utils.isdebug.md) |  |
+|  [isNil(val)](./js-utils.isnil.md) |  |
+|  [makeDict(map)](./js-utils.makedict.md) | Turns a map or dict into a dict |
+|  [makeMap(val)](./js-utils.makemap.md) | Clone a map or map-like object into a new map. |
+|  [mergeList(parts)](./js-utils.mergelist.md) | Merge arguments, which may or may not be arrays, into one return that is definitely an array. |
+|  [mergeMap(target, source)](./js-utils.mergemap.md) |  |
+|  [mustCoalesce(values)](./js-utils.mustcoalesce.md) | Return the first value that is not nil. |
+|  [mustExist(val)](./js-utils.mustexist.md) | Assert that a variable is not nil and return the value. |
+|  [mustFind(list, predicate)](./js-utils.mustfind.md) | Find a value matching the given predicate or throw. |
+|  [mustGet(map, key)](./js-utils.mustget.md) | Get an element from a Map and guard against nil values. |
+|  [pushMergeMap(args)](./js-utils.pushmergemap.md) |  |
+|  [removePid(path)](./js-utils.removepid.md) |  |
+|  [setOrPush(map, key, val)](./js-utils.setorpush.md) | Set a map key to a new array or push to the existing value. |
+|  [signal(signals)](./js-utils.signal.md) |  |
+|  [spyLogger(spies)](./js-utils.spylogger.md) |  |
+|  [timeout(ms, oper)](./js-utils.timeout.md) | Reject after a set amount of time if the original promise has not yet resolved. |
+|  [waitForChild(child)](./js-utils.waitforchild.md) |  |
+|  [writePid(path)](./js-utils.writepid.md) |  |
+
+## Interfaces
+
+|  Interface | Description |
+|  --- | --- |
+|  [Dict](./js-utils.dict.md) |  |
+|  [ExternalModule](./js-utils.externalmodule.md) |  |
+
+## Variables
+
+|  Variable | Description |
+|  --- | --- |
+|  [SIGNAL\_RELOAD](./js-utils.signal_reload.md) |  |
+|  [SIGNAL\_RESET](./js-utils.signal_reset.md) |  |
+|  [SIGNAL\_STOP](./js-utils.signal_stop.md) |  |
+
+## Type Aliases
+
+|  Type Alias | Description |
+|  --- | --- |
+|  [MapLike](./js-utils.maplike.md) | A <code>Map</code> or dictionary object with string keys and <code>TVal</code> values. |
+|  [ModuleCtor](./js-utils.modulector.md) |  |
+|  [Nil](./js-utils.nil.md) | Unset value. |
+|  [Optional](./js-utils.optional.md) | Value that may be nil. |
+

docs/api/js-utils.mergelist.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [mergeList](./js-utils.mergelist.md)
+
+## mergeList() function
+
+Merge arguments, which may or may not be arrays, into one return that is definitely an array.
+
+<b>Signature:</b>
+
+```typescript
+export declare function mergeList<TItem>(...parts: Array<TItem | Array<TItem>>): Array<TItem>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  parts | <code>Array&lt;TItem &#124; Array&lt;TItem&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Array<TItem>`
+

docs/api/js-utils.mergemap.md

@@ -0,0 +1,23 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [mergeMap](./js-utils.mergemap.md)
+
+## mergeMap() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function mergeMap<TKey, TVal>(target: Map<TKey, TVal>, source: Map<TKey, TVal> | Array<[TKey, TVal]>): Map<TKey, TVal>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  target | <code>Map&lt;TKey, TVal&gt;</code> |  |
+|  source | <code>Map&lt;TKey, TVal&gt; &#124; Array&lt;[TKey, TVal]&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Map<TKey, TVal>`
+

docs/api/js-utils.missingkeyerror._constructor_.md

@@ -0,0 +1,21 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [MissingKeyError](./js-utils.missingkeyerror.md) &gt; [(constructor)](./js-utils.missingkeyerror._constructor_.md)
+
+## MissingKeyError.(constructor)
+
+Constructs a new instance of the `MissingKeyError` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(msg?: string, ...nested: Array<Error>);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  msg | <code>string</code> |  |
+|  nested | <code>Array&lt;Error&gt;</code> |  |
+

docs/api/js-utils.missingkeyerror.md

@@ -0,0 +1,18 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [MissingKeyError](./js-utils.missingkeyerror.md)
+
+## MissingKeyError class
+
+<b>Signature:</b>
+
+```typescript
+export declare class MissingKeyError extends BaseError 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(msg, nested)](./js-utils.missingkeyerror._constructor_.md) |  | Constructs a new instance of the <code>MissingKeyError</code> class |
+

docs/api/js-utils.modulector.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [ModuleCtor](./js-utils.modulector.md)
+
+## ModuleCtor type
+
+<b>Signature:</b>
+
+```typescript
+export declare type ModuleCtor = new (data: unknown) => Module;
+```

docs/api/js-utils.mustcoalesce.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [mustCoalesce](./js-utils.mustcoalesce.md)
+
+## mustCoalesce() function
+
+Return the first value that is not nil.
+
+<b>Signature:</b>
+
+```typescript
+export declare function mustCoalesce<T>(...values: Array<Optional<T>>): T;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  values | <code>Array&lt;Optional&lt;T&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`T`
+

docs/api/js-utils.mustexist.md

@@ -0,0 +1,30 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [mustExist](./js-utils.mustexist.md)
+
+## mustExist() function
+
+Assert that a variable is not nil and return the value.
+
+<b>Signature:</b>
+
+```typescript
+export declare function mustExist<T>(val: Optional<T>): T;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  val | <code>Optional&lt;T&gt;</code> |  |
+
+<b>Returns:</b>
+
+`T`
+
+val
+
+## Exceptions
+
+NotFoundError
+

docs/api/js-utils.mustfind.md

@@ -0,0 +1,25 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [mustFind](./js-utils.mustfind.md)
+
+## mustFind() function
+
+Find a value matching the given predicate or throw.
+
+<b>Signature:</b>
+
+```typescript
+export declare function mustFind<TVal>(list: Array<Optional<TVal>>, predicate: PredicateC1<TVal>): TVal;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  list | <code>Array&lt;Optional&lt;TVal&gt;&gt;</code> |  |
+|  predicate | <code>PredicateC1&lt;TVal&gt;</code> |  |
+
+<b>Returns:</b>
+
+`TVal`
+

docs/api/js-utils.mustget.md

@@ -0,0 +1,25 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [mustGet](./js-utils.mustget.md)
+
+## mustGet() function
+
+Get an element from a Map and guard against nil values.
+
+<b>Signature:</b>
+
+```typescript
+export declare function mustGet<TKey, TVal>(map: Map<TKey, TVal>, key: TKey): TVal;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  map | <code>Map&lt;TKey, TVal&gt;</code> |  |
+|  key | <code>TKey</code> |  |
+
+<b>Returns:</b>
+
+`TVal`
+

docs/api/js-utils.nil.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [Nil](./js-utils.nil.md)
+
+## Nil type
+
+Unset value.
+
+<b>Signature:</b>
+
+```typescript
+export declare type Nil = null | undefined;
+```

docs/api/js-utils.notfounderror._constructor_.md

@@ -0,0 +1,21 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [NotFoundError](./js-utils.notfounderror.md) &gt; [(constructor)](./js-utils.notfounderror._constructor_.md)
+
+## NotFoundError.(constructor)
+
+Constructs a new instance of the `NotFoundError` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(msg?: string, ...nested: Array<Error>);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  msg | <code>string</code> |  |
+|  nested | <code>Array&lt;Error&gt;</code> |  |
+

docs/api/js-utils.notfounderror.md

@@ -0,0 +1,18 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [NotFoundError](./js-utils.notfounderror.md)
+
+## NotFoundError class
+
+<b>Signature:</b>
+
+```typescript
+export declare class NotFoundError extends BaseError 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(msg, nested)](./js-utils.notfounderror._constructor_.md) |  | Constructs a new instance of the <code>NotFoundError</code> class |
+

docs/api/js-utils.notimplementederror._constructor_.md

@@ -0,0 +1,21 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [NotImplementedError](./js-utils.notimplementederror.md) &gt; [(constructor)](./js-utils.notimplementederror._constructor_.md)
+
+## NotImplementedError.(constructor)
+
+Constructs a new instance of the `NotImplementedError` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(msg?: string, ...nested: Array<Error>);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  msg | <code>string</code> |  |
+|  nested | <code>Array&lt;Error&gt;</code> |  |
+

docs/api/js-utils.notimplementederror.md

@@ -0,0 +1,18 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [NotImplementedError](./js-utils.notimplementederror.md)
+
+## NotImplementedError class
+
+<b>Signature:</b>
+
+```typescript
+export declare class NotImplementedError extends BaseError 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(msg, nested)](./js-utils.notimplementederror._constructor_.md) |  | Constructs a new instance of the <code>NotImplementedError</code> class |
+

docs/api/js-utils.optional.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [Optional](./js-utils.optional.md)
+
+## Optional type
+
+Value that may be nil.
+
+<b>Signature:</b>
+
+```typescript
+export declare type Optional<T> = T | Nil;
+```

docs/api/js-utils.pushmergemap.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [pushMergeMap](./js-utils.pushmergemap.md)
+
+## pushMergeMap() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function pushMergeMap<TKey, TVal>(...args: Array<Map<TKey, TVal | Array<TVal>>>): Map<TKey, Array<TVal>>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  args | <code>Array&lt;Map&lt;TKey, TVal &#124; Array&lt;TVal&gt;&gt;&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Map<TKey, Array<TVal>>`
+

docs/api/js-utils.removepid.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [removePid](./js-utils.removepid.md)
+
+## removePid() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function removePid(path: string): Promise<void>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  path | <code>string</code> |  |
+
+<b>Returns:</b>
+
+`Promise<void>`
+

docs/api/js-utils.setorpush.md

@@ -0,0 +1,26 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [setOrPush](./js-utils.setorpush.md)
+
+## setOrPush() function
+
+Set a map key to a new array or push to the existing value.
+
+<b>Signature:</b>
+
+```typescript
+export declare function setOrPush<TKey, TVal>(map: Map<TKey, Array<TVal>>, key: TKey, val: TVal | Array<TVal>): void;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  map | <code>Map&lt;TKey, Array&lt;TVal&gt;&gt;</code> |  |
+|  key | <code>TKey</code> |  |
+|  val | <code>TVal &#124; Array&lt;TVal&gt;</code> |  |
+
+<b>Returns:</b>
+
+`void`
+

docs/api/js-utils.signal.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [signal](./js-utils.signal.md)
+
+## signal() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function signal(...signals: Array<NodeJS.Signals>): Promise<NodeJS.Signals>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  signals | <code>Array&lt;NodeJS.Signals&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Promise<NodeJS.Signals>`
+

docs/api/js-utils.signal_reload.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [SIGNAL\_RELOAD](./js-utils.signal_reload.md)
+
+## SIGNAL\_RELOAD variable
+
+<b>Signature:</b>
+
+```typescript
+SIGNAL_RELOAD: NodeJS.Signals
+```

docs/api/js-utils.signal_reset.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [SIGNAL\_RESET](./js-utils.signal_reset.md)
+
+## SIGNAL\_RESET variable
+
+<b>Signature:</b>
+
+```typescript
+SIGNAL_RESET: NodeJS.Signals
+```

docs/api/js-utils.signal_stop.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [SIGNAL\_STOP](./js-utils.signal_stop.md)
+
+## SIGNAL\_STOP variable
+
+<b>Signature:</b>
+
+```typescript
+SIGNAL_STOP: NodeJS.Signals
+```

docs/api/js-utils.spylogger.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [spyLogger](./js-utils.spylogger.md)
+
+## spyLogger() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function spyLogger(spies: Partial<Logger>): Logger;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  spies | <code>Partial&lt;Logger&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Logger`
+

docs/api/js-utils.timeout.md

@@ -0,0 +1,25 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [timeout](./js-utils.timeout.md)
+
+## timeout() function
+
+Reject after a set amount of time if the original promise has not yet resolved.
+
+<b>Signature:</b>
+
+```typescript
+export declare function timeout<T>(ms: number, oper: Promise<T>): Promise<T>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  ms | <code>number</code> |  |
+|  oper | <code>Promise&lt;T&gt;</code> |  |
+
+<b>Returns:</b>
+
+`Promise<T>`
+

docs/api/js-utils.timeouterror._constructor_.md

@@ -0,0 +1,21 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [TimeoutError](./js-utils.timeouterror.md) &gt; [(constructor)](./js-utils.timeouterror._constructor_.md)
+
+## TimeoutError.(constructor)
+
+Constructs a new instance of the `TimeoutError` class
+
+<b>Signature:</b>
+
+```typescript
+constructor(msg?: string, ...nested: Array<Error>);
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  msg | <code>string</code> |  |
+|  nested | <code>Array&lt;Error&gt;</code> |  |
+

docs/api/js-utils.timeouterror.md

@@ -0,0 +1,18 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [TimeoutError](./js-utils.timeouterror.md)
+
+## TimeoutError class
+
+<b>Signature:</b>
+
+```typescript
+export declare class TimeoutError extends BaseError 
+```
+
+## Constructors
+
+|  Constructor | Modifiers | Description |
+|  --- | --- | --- |
+|  [(constructor)(msg, nested)](./js-utils.timeouterror._constructor_.md) |  | Constructs a new instance of the <code>TimeoutError</code> class |
+

docs/api/js-utils.waitforchild.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [waitForChild](./js-utils.waitforchild.md)
+
+## waitForChild() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function waitForChild(child: ChildProcessWithoutNullStreams): Promise<ChildResult>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  child | <code>ChildProcessWithoutNullStreams</code> |  |
+
+<b>Returns:</b>
+
+`Promise<ChildResult>`
+

docs/api/js-utils.writepid.md

@@ -0,0 +1,22 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@apextoaster/js-utils](./js-utils.md) &gt; [writePid](./js-utils.writepid.md)
+
+## writePid() function
+
+<b>Signature:</b>
+
+```typescript
+export declare function writePid(path: string): Promise<void>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  path | <code>string</code> |  |
+
+<b>Returns:</b>
+
+`Promise<void>`
+

docs/api/rollup-template.md

@@ -1,6 +0,0 @@
-<!-- Do not edit this file. It is automatically generated by API Documenter. -->
-
-[Home](./index.md) &gt; [@apextoaster/rollup-template](./rollup-template.md)
-
-## rollup-template package
-

package.json

@@ -2,7 +2,7 @@
   "name": "@apextoaster/js-utils",
   "version": "0.1.1",
   "description": "utility functions",
-  "main": "out/index.js",
+  "main": "out/main.js",
   "types": "out/index.d.ts",
   "typings": "out/index.d.ts",
   "directories": {
@@ -28,6 +28,7 @@
     "@types/chai-as-promised": "7.1.2",
     "@types/lodash": "^4.14.149",
     "@types/mocha": "7.0.2",
+    "@types/node": "^13.9.5",
     "@types/sinon-chai": "3.2.3",
     "@types/source-map-support": "0.5.1",
     "@typescript-eslint/eslint-plugin": "2.25.0",

src/app.ts

@@ -1,9 +1,7 @@
-import JSON_DATA from './resource/json.json';
-import YAML_DATA from './resource/yaml.yml';
 import { VERSION_INFO } from './version';
 
 export async function main(argv: Array<string>): Promise<number> {
   /* eslint-disable-next-line no-console */
-  console.log('Hello World!', VERSION_INFO, JSON_DATA, YAML_DATA, argv);
+  console.log('Hello World!', VERSION_INFO, argv);
   return 1;
 }

src/entity/README.md

@@ -1,3 +0,0 @@
-# Entity
-
-Database entities.

src/error/ChildProcessError.ts

@@ -0,0 +1,7 @@
+import { BaseError } from 'noicejs';
+
+export class ChildProcessError extends BaseError {
+  constructor(msg = 'child process exited with error status', ...nested: Array<Error>) {
+    super(msg, ...nested);
+  }
+}

src/error/InvalidArgumentError.ts

@@ -0,0 +1,7 @@
+import { BaseError } from 'noicejs';
+
+export class InvalidArgumentError extends BaseError {
+  constructor(msg = 'invalid argument passed', ...nested: Array<Error>) {
+    super(msg, ...nested);
+  }
+}

src/error/MissingKeyError.ts

@@ -0,0 +1,7 @@
+import { BaseError } from 'noicejs';
+
+export class MissingKeyError extends BaseError {
+  constructor(msg = 'missing key', ...nested: Array<Error>) {
+    super(msg, ...nested);
+  }
+}

src/error/NotFoundError.ts

@@ -0,0 +1,7 @@
+import { BaseError } from 'noicejs';
+
+export class NotFoundError extends BaseError {
+  constructor(msg = 'value not found', ...nested: Array<Error>) {
+    super(msg, ...nested);
+  }
+}

src/error/NotImplementedError.ts

@@ -0,0 +1,7 @@
+import { BaseError } from 'noicejs';
+
+export class NotImplementedError extends BaseError {
+  constructor(msg = 'method not implemented', ...nested: Array<Error>) {
+    super(msg, ...nested);
+  }
+}

src/error/TimeoutError.ts

@@ -0,0 +1,7 @@
+import { BaseError } from 'noicejs';
+
+export class TimeoutError extends BaseError {
+  constructor(msg = 'operation timed out', ...nested: Array<Error>) {
+    super(msg, ...nested);
+  }
+}

src/index.ts

@@ -1,12 +1,63 @@
-import { main } from './app';
+export { ChildProcessError } from './error/ChildProcessError';
+export { InvalidArgumentError } from './error/InvalidArgumentError';
+export { MissingKeyError } from './error/MissingKeyError';
+export { NotFoundError } from './error/NotFoundError';
+export { NotImplementedError } from './error/NotImplementedError';
+export { TimeoutError } from './error/TimeoutError';
 
-const STATUS_ERROR = 1;
+export {
+  AsyncTracker,
+} from './test/AsyncTracker';
+export {
+  getTestLogger,
+  spyLogger,
+} from './test/Logger';
 
-/**
+export {
- * This is the main entry-point to the program and the only file not included in the main bundle.
+  Nil,
- */
+  Optional,
-main(process.argv).then((status) => process.exit(status)).catch((err: Error) => {
+  countOf,
-  // eslint-disable-next-line no-console
+  defaultWhen,
-  console.error('uncaught error during main:', err);
+  doesExist,
-  process.exit(STATUS_ERROR);
+  filterNil,
-});
+  isNil,
+  mergeList,
+  mustCoalesce,
+  mustExist,
+  mustFind,
+} from './utils';
+export {
+  ArrayMapper,
+} from './utils/ArrayMapper';
+export {
+  defer,
+  timeout,
+} from './utils/Async';
+export {
+  concat,
+  encode,
+} from './utils/Buffer';
+export { waitForChild } from './utils/Child';
+export { ExternalModule, ModuleCtor } from './utils/ExternalModule';
+export { isDebug } from './utils/Env';
+export {
+  Dict,
+  MapLike,
+  entriesOf,
+  makeDict,
+  makeMap,
+  mergeMap,
+  mustGet,
+  pushMergeMap,
+  setOrPush,
+} from './utils/Map';
+export {
+  removePid,
+  writePid,
+} from './utils/PidFile';
+export {
+  SIGNAL_RELOAD,
+  SIGNAL_RESET,
+  SIGNAL_STOP,
+  signal,
+} from './utils/Signal';

src/lib.ts

@@ -1,5 +0,0 @@
-import { VERSION_INFO } from './version';
-
-export default {
-  VERSION_INFO,
-};

src/migration/README.md

@@ -1,3 +0,0 @@
-# Migration
-
-Database schema migrations for the entities.

src/module/README.md

@@ -1,3 +0,0 @@
-# Module
-
-Dependency injection modules.

src/resource/json.json

@@ -1,3 +0,0 @@
-{
-  "foo": {}
-}

src/resource/yaml.yml

@@ -1 +0,0 @@
-foo: {}

src/test/AsyncTracker.ts

@@ -0,0 +1,79 @@
+import { AsyncHook, createHook } from 'async_hooks';
+
+import { isNil } from '../utils';
+import { isDebug } from '../utils/Env';
+
+export interface TrackedResource {
+  source: string;
+  triggerAsyncId: number;
+  type: string;
+}
+
+/**
+ * Async resource tracker using  node's internal hooks.
+ *
+ * This probably won't work in a browser. It does not hold references to the resource, to avoid leaks.
+ * Adapted from https://gist.github.com/boneskull/7fe75b63d613fa940db7ec990a5f5843#file-async-dump-js
+ */
+export class AsyncTracker {
+  public static getStack(): string {
+    const err = new Error();
+    if (isNil(err.stack)) {
+      return 'no stack trace available';
+    } else {
+      return err.stack; // TODO: filterStack(err.stack);
+    }
+  }
+
+  private readonly hook: AsyncHook;
+  private readonly resources: Map<number, TrackedResource>;
+
+  constructor() {
+    this.resources = new Map();
+    this.hook = createHook({
+      destroy: (id: number) => {
+        this.resources.delete(id);
+      },
+      init: (id: number, type: string, triggerAsyncId: number) => {
+        const source = AsyncTracker.getStack();
+        // @TODO: exclude async hooks, including this one
+        this.resources.set(id, {
+          source,
+          triggerAsyncId,
+          type,
+        });
+      },
+      promiseResolve: (id: number) => {
+        this.resources.delete(id);
+      },
+    });
+  }
+
+  public clear() {
+    this.resources.clear();
+  }
+
+  public disable() {
+    this.hook.disable();
+  }
+
+  /* eslint-disable no-console, no-invalid-this */
+  public dump() {
+    console.error(`tracking ${this.resources.size} async resources`);
+    this.resources.forEach((res, id) => {
+      console.error(`${id}: ${res.type}`);
+      if (isDebug()) {
+        console.error(res.source);
+        console.error('\n');
+      }
+    });
+  }
+
+  public enable() {
+    this.hook.enable();
+  }
+
+  public get size(): number {
+    return this.resources.size;
+  }
+}

src/test/Logger.ts

@@ -0,0 +1,19 @@
+import { ConsoleLogger, Logger, NullLogger } from 'noicejs';
+
+const ENV_DEBUG = 'DEBUG';
+
+export function getTestLogger(verbose = false): Logger {
+  if (verbose || process.env[ENV_DEBUG] === 'TRUE') {
+    return new ConsoleLogger();
+  } else {
+    return new NullLogger();
+  }
+}
+
+export function spyLogger(spies: Partial<Logger>): Logger {
+  const logger = {
+    ...spies,
+    child: () => logger,
+  } as Logger;
+  return logger;
+}

src/utils/ArrayMapper.ts

@@ -0,0 +1,41 @@
+import { setOrPush } from './Map';
+
+export interface ArrayMapperOptions {
+  rest: string;
+  skip: number;
+  take: Array<string>;
+}
+
+export class ArrayMapper {
+  public readonly rest: string;
+  public readonly skip: number;
+  public readonly take: Array<string>;
+
+  constructor(options: ArrayMapperOptions) {
+    this.rest = options.rest;
+    this.skip = options.skip;
+    this.take = Array.from(options.take);
+  }
+
+  public map(input: Array<string>): Map<string, Array<string>> {
+    const result = new Map();
+    input.forEach((it, idx) => {
+      if (idx < this.skip) {
+        return;
+      }
+
+      const skipdx = idx - this.skip;
+      if (skipdx < this.take.length) {
+        setOrPush(result, this.take[skipdx], it);
+      } else {
+        setOrPush(result, this.rest, it);
+      }
+    });
+
+    if (!result.has(this.rest)) {
+      result.set(this.rest, []);
+    }
+
+    return result;
+  }
+}

src/utils/Async.ts

@@ -0,0 +1,38 @@
+import { TimeoutError } from '../error/TimeoutError';
+
+/**
+ * Resolve after a set amount of time.
+ */
+export function defer<T = undefined>(ms: number, val?: T): Promise<T> {
+  return new Promise((res, rej) => {
+    setTimeout(() => {
+      res(val);
+    }, ms);
+  });
+}
+
+/**
+ * Reject after a set amount of time if the original promise has not yet resolved.
+ */
+export function timeout<T>(ms: number, oper: Promise<T>): Promise<T> {
+  const limit = new Promise<T>((res, rej) => {
+    setTimeout(() => {
+      rej(new TimeoutError());
+    }, ms);
+  });
+
+  return Promise.race([limit, oper]);
+}
+
+export async function waitFor(cb: () => boolean, step: number, count: number): Promise<void> {
+  let accum = 0;
+  while (accum < count) {
+    await defer(step);
+    if (cb()) {
+      return;
+    }
+    accum += 1;
+  }
+
+  throw new TimeoutError();
+}

src/utils/Buffer.ts

@@ -0,0 +1,12 @@
+export function concat(chunks: Array<Buffer>): Buffer {
+  const sum = chunks.map((it) => it.length).reduce((p, c) => p + c, 0);
+  return Buffer.concat(chunks, sum);
+}
+
+export function encode(chunks: Array<Buffer>, encoding: string): string {
+  if (chunks.length === 0) {
+    return '';
+  }
+
+  return concat(chunks).toString(encoding);
+}

src/utils/Child.ts

@@ -0,0 +1,84 @@
+import { ChildProcessWithoutNullStreams, spawn } from 'child_process';
+import { BaseError } from 'noicejs';
+import { Writable } from 'stream';
+
+import { doesExist, Optional } from '.';
+import { ChildProcessError } from '../error/ChildProcessError';
+import { encode } from './Buffer';
+import { NameValuePair } from './Map';
+
+export interface ChildOptions {
+  args: Array<string>;
+  command: string;
+  cwd: string;
+  env: Array<NameValuePair<string>>;
+  timeout: number;
+}
+
+export interface ChildResult {
+  status: number;
+  stderr: string;
+  stdout: string;
+}
+
+export type ChildSpawner = typeof spawn;
+
+const CHILD_ENCODING = 'utf-8';
+const CHILD_EVENT = 'child process emitted error event';
+const CHILD_STATUS = 'child process exited with error status';
+const CHILD_OUTPUT = 'child process emitted error output';
+
+export function waitForChild(child: ChildProcessWithoutNullStreams): Promise<ChildResult> {
+  return new Promise((res, rej) => {
+    const stderr: Array<Buffer> = [];
+    const stdout: Array<Buffer> = [];
+
+    child.stderr.on('data', (chunk) => {
+      stderr.push(chunk);
+    });
+
+    child.stdout.on('data', (chunk) => {
+      stdout.push(chunk);
+    });
+
+    child.on('error', (err: Error | number) => {
+      if (err instanceof Error) {
+        rej(new ChildProcessError(CHILD_EVENT, err));
+      }
+    });
+
+    child.on('close', (status: number) => {
+      const errors = encode(stderr, CHILD_ENCODING);
+      if (status > 0) {
+        const msg = `${CHILD_STATUS}: ${status}`;
+        rej(new ChildProcessError(msg, new BaseError(errors)));
+        return;
+      }
+
+      if (errors.length > 0) {
+        rej(new ChildProcessError(CHILD_OUTPUT, new BaseError(errors)));
+        return;
+      }
+
+      res({
+        status,
+        stderr: errors,
+        stdout: encode(stdout, CHILD_ENCODING),
+      });
+    });
+  });
+}
+
+export function writeValue(stream: Writable, value: string): Promise<boolean> {
+  return new Promise<boolean>((res, rej) => {
+    stream.write(value, (err: Optional<Error>) => {
+      if (doesExist(err)) {
+        rej(err);
+      } else {
+        stream.end(() => {
+          res(true);
+        });
+      }
+    });
+  });
+}

src/utils/Env.ts

@@ -0,0 +1,3 @@
+export function isDebug() {
+  return Reflect.has(process.env, 'DEBUG');
+}

src/utils/ExternalModule.ts

@@ -0,0 +1,14 @@
+import { Module } from 'noicejs';
+
+export interface ExternalModule {
+  data?: unknown;
+  export: string;
+  require: string;
+}
+
+export type ModuleCtor = new (data: unknown) => Module;
+
+export function isModule(it: object): it is ModuleCtor {
+  const p = Reflect.getPrototypeOf(it);
+  return p === Module || p instanceof Module;
+}

src/utils/Map.ts

@@ -0,0 +1,185 @@
+import { isMap, isObject, isString } from 'lodash';
+
+import { doesExist, isNil, mergeList, mustExist, Optional } from '.';
+import { NotFoundError } from '../error/NotFoundError';
+
+export interface Dict<TVal> {
+  [key: string]: TVal;
+}
+
+/**
+ * A `Map` or dictionary object with string keys and `TVal` values.
+ */
+export type MapLike<TVal> = Map<string, TVal> | Dict<TVal>;
+
+/**
+ * Get an element from a Map and guard against nil values.
+ */
+export function mustGet<TKey, TVal>(map: Map<TKey, TVal>, key: TKey): TVal {
+  const val = map.get(key);
+  return mustExist(val);
+}
+
+export function getOrDefault<TKey, TVal>(map: Map<TKey, TVal>, key: TKey, defaultValue: TVal): TVal {
+  if (map.has(key)) {
+    const data = map.get(key);
+    if (doesExist(data)) {
+      return data;
+    }
+  }
+
+  return defaultValue;
+}
+
+export function getHead<TKey, TVal>(map: Map<TKey, Array<TVal>>, key: TKey): TVal {
+  const value = map.get(key);
+  if (isNil(value) || value.length === 0) {
+    throw new NotFoundError();
+  }
+  return value[0];
+}
+
+export function getHeadOrDefault<TKey, TVal>(map: Map<TKey, Array<Optional<TVal>>>, key: TKey, defaultValue: TVal): TVal {
+  if (!map.has(key)) {
+    return defaultValue;
+  }
+
+  const data = map.get(key);
+  if (isNil(data)) {
+    return defaultValue;
+  }
+
+  const [head] = data;
+  if (isNil(head)) {
+    return defaultValue;
+  }
+
+  return head;
+}
+
+/**
+ * Set a map key to a new array or push to the existing value.
+ * @param map The destination map and source of existing values.
+ * @param key The key to get and set.
+ * @param val The value to add.
+ */
+export function setOrPush<TKey, TVal>(map: Map<TKey, Array<TVal>>, key: TKey, val: TVal | Array<TVal>) {
+  const prev = map.get(key);
+  if (doesExist(prev)) {
+    map.set(key, mergeList(prev, val));
+  } else {
+    if (Array.isArray(val)) {
+      map.set(key, val);
+    } else {
+      map.set(key, [val]);
+    }
+  }
+}
+
+export function mergeMap<TKey, TVal>(target: Map<TKey, TVal>, source: Map<TKey, TVal> | Array<[TKey, TVal]>) {
+  for (const [k, v] of source) {
+    target.set(k, v);
+  }
+
+  return target;
+}
+
+export function pushMergeMap<TKey, TVal>(...args: Array<Map<TKey, TVal | Array<TVal>>>): Map<TKey, Array<TVal>> {
+  const out = new Map();
+  for (const arg of args) {
+    for (const [key, val] of arg) {
+      setOrPush(out, key, val);
+    }
+  }
+  return out;
+}
+
+/**
+ * Clone a map or map-like object into a new map.
+ */
+export function makeMap<TVal>(val: Optional<MapLike<TVal>>): Map<string, TVal> {
+  // nil: empty map
+  if (isNil(val)) {
+    return new Map();
+  }
+
+  // already a map: make a copy
+  if (isMap(val)) {
+    return new Map(val.entries());
+  }
+
+  // otherwise: dict
+  return new Map(Object.entries(val));
+}
+
+/**
+ * Turns a map or dict into a dict
+ */
+export function makeDict<TVal>(map: Optional<MapLike<TVal>>): Dict<TVal> {
+  if (isNil(map)) {
+    return {};
+  }
+
+  if (isMap(map)) {
+    const result: Dict<TVal> = {};
+    for (const [key, val] of map) {
+      result[key] = val;
+    }
+    return result;
+  }
+
+  return map;
+}
+
+export interface NameValuePair<TVal> {
+  name: string;
+  value: TVal;
+}
+
+export function pairsToMap<TVal>(pairs: Array<NameValuePair<TVal>>): Map<string, TVal> {
+  const map = new Map();
+  for (const p of pairs) {
+    map.set(p.name, p.value);
+  }
+  return map;
+}
+
+export function dictValuesToArrays<TVal>(map: MapLike<TVal>): Dict<Array<TVal>> {
+  const data: Dict<Array<TVal>> = {};
+  for (const [key, value] of makeMap(map)) {
+    if (Array.isArray(value)) {
+      data[key] = value;
+    } else {
+      data[key] = [value];
+    }
+  }
+
+  return data;
+}
+
+export function normalizeMap(map: MapLike<unknown>): Dict<Array<string>> {
+  const data: Dict<Array<string>> = {};
+  for (const [key, value] of makeMap(map)) {
+    if (Array.isArray(value)) {
+      data[key] = value;
+    } else if (isString(value)) {
+      data[key] = [value];
+    } else if (isObject(value)) {
+      data[key] = [value.toString()];
+    }
+  }
+
+  return data;
+}
+
+export function entriesOf<TVal>(map: Optional<MapLike<TVal>>): Array<[string, TVal]> {
+  if (map instanceof Map) {
+    return Array.from(map.entries());
+  }
+
+  if (map instanceof Object) {
+    return Object.entries(map);
+  }
+
+  return [];
+}

src/utils/PidFile.ts

@@ -0,0 +1,36 @@
+import { open, unlink, write } from 'fs';
+import { pid } from 'process';
+
+import { doesExist, Optional } from '.';
+
+type OptionalErrno = Optional<NodeJS.ErrnoException>;
+
+export async function writePid(path: string): Promise<void> {
+  return new Promise((res, rej) => {
+    open(path, 'wx', (openErr: OptionalErrno, fd: number) => {
+      if (doesExist(openErr)) {
+        rej(openErr);
+      } else {
+        write(fd, pid.toString(), 0, 'utf8', (writeErr: OptionalErrno) => {
+          if (doesExist(writeErr)) {
+            rej(writeErr);
+          } else {
+            res();
+          }
+        });
+      }
+    });
+  });
+}
+
+export async function removePid(path: string): Promise<void> {
+  return new Promise((res, rej) => {
+    unlink(path, (err: OptionalErrno) => {
+      if (doesExist(err)) {
+        rej(err);
+      } else {
+        res();
+      }
+    });
+  });
+}

src/utils/Reflect.ts

@@ -0,0 +1,36 @@
+import { isFunction } from 'lodash';
+
+import { doesExist, isNil } from '.';
+
+export function getConstructor(val: object) {
+  return val.constructor;
+}
+
+export function getMethods<TValue extends object>(value: TValue): Set<Function> {
+  const methods = new Set<Function>();
+
+  for (const name of Object.getOwnPropertyNames(value)) {
+    const desc = Object.getOwnPropertyDescriptor(value, name);
+    if (isNil(desc)) {
+      continue;
+    }
+
+    const method = desc.value;
+    if (isFunction(method)) {
+      methods.add(method);
+    }
+  }
+
+  const proto = Reflect.getPrototypeOf(value);
+  if (proto !== value && doesExist(proto)) {
+    for (const m of getMethods(proto)) {
+      methods.add(m);
+    }
+  }
+
+  return methods;
+}
+
+export function constructorName(val: object) {
+  return getConstructor(Reflect.getPrototypeOf(val)).name;
+}

src/utils/Signal.ts

@@ -0,0 +1,18 @@
+export const SIGNAL_RELOAD: NodeJS.Signals = 'SIGHUP';
+export const SIGNAL_RESET: NodeJS.Signals = 'SIGINT';
+export const SIGNAL_STOP: NodeJS.Signals = 'SIGTERM';
+
+export function signal(...signals: Array<NodeJS.Signals>): Promise<NodeJS.Signals> {
+  return new Promise((res, _) => {
+    function handler(fired: NodeJS.Signals) {
+      for (const s of signals) {
+        process.removeListener(s, handler);
+      }
+      res(fired);
+    }
+
+    for (const sig of signals) {
+      process.on(sig, handler);
+    }
+  });
+}

src/utils/String.ts

@@ -0,0 +1,23 @@
+
+export function leftPad(val: string, min = 8, fill = '0'): string {
+  if (val.length < min) {
+    const len = min - val.length;
+    const pre = Array(len).fill(fill).join('').slice(0, len);
+    return `${pre}${val}`;
+  } else {
+    return val;
+  }
+}
+
+export function trim(val: string, max: number, tail = '...'): string {
+  if (val.length <= max) {
+    return val;
+  }
+
+  if (max < tail.length) {
+    return val.substr(0, max);
+  }
+
+  const start = val.substr(0, max - tail.length);
+  return `${start}${tail}`;
+}

src/utils/index.ts

@@ -0,0 +1,119 @@
+import { NotFoundError } from '../error/NotFoundError';
+
+/**
+ * Unset value.
+ */
+/* eslint-disable-next-line @typescript-eslint/ban-types */
+export type Nil = null | undefined;
+
+/**
+ * Value that may be nil.
+ */
+export type Optional<T> = T | Nil;
+
+/**
+ * Comparison (filter) predicate for a single value.
+ */
+export type PredicateC1<TVal> = (val: TVal, idx: number, list: Array<TVal>) => boolean;
+
+/**
+ * Comparison (sort) predicate for two values.
+ */
+export type PredicateC2<TVal> = (pval: TVal, nval: TVal, idx: number, list: Array<TVal>) => number;
+
+/**
+ * Reduction predicate for two values.
+ */
+export type PredicateR2<TVal> = (pval: TVal, nval: TVal, idx: number, list: Array<TVal>) => TVal;
+
+/* eslint-disable-next-line @typescript-eslint/ban-types */
+export function isNil<T>(val: Optional<T>): val is Nil {
+  /* eslint-disable-next-line no-null/no-null */
+  return val === null || val === undefined;
+}
+
+/**
+ * Calculate the "length" of an array or value.
+ *
+ * Arrays return their length, single values return 1, and nil values return 0.
+ * This counts the number of elements that setOrPush would add.
+ */
+export function countOf(val: unknown): number {
+  if (Array.isArray(val)) {
+    return val.length;
+  }
+
+  if (doesExist(val)) {
+    return 1;
+  }
+
+  return 0;
+}
+
+export function defaultWhen<TVal>(condition: boolean, ...items: Array<TVal>): TVal {
+  if (condition) {
+    return items[0];
+  } else {
+    return items[1];
+  }
+}
+
+/**
+ * Remove any null or undefined items from the list.
+ */
+export function filterNil<TItem>(list: ArrayLike<Optional<TItem>>): Array<TItem> {
+  return Array.from(list).filter(doesExist);
+}
+
+/**
+ * Merge arguments, which may or may not be arrays, into one return that is definitely an array.
+ */
+export function mergeList<TItem>(...parts: Array<TItem | Array<TItem>>): Array<TItem> {
+  const out = [];
+
+  for (const part of parts) {
+    if (Array.isArray(part)) {
+      out.push(...part);
+    } else {
+      out.push(part);
+    }
+  }
+
+  return out;
+}
+
+/**
+ * Find a value matching the given predicate or throw.
+ */
+export function mustFind<TVal>(list: Array<Optional<TVal>>, predicate: PredicateC1<TVal>): TVal {
+  const val = filterNil(list).find(predicate);
+  return mustExist(val);
+}
+
+/**
+ * Check if a variable is not nil.
+ */
+export function doesExist<T>(val: Optional<T>): val is T {
+  return !isNil(val);
+}
+
+/**
+ * Assert that a variable is not nil and return the value.
+ *
+ * @throws NotFoundError
+ * @returns val
+ */
+export function mustExist<T>(val: Optional<T>): T {
+  if (isNil(val)) {
+    throw new NotFoundError();
+  }
+
+  return val;
+}
+
+/**
+ * Return the first value that is not nil.
+ */
+export function mustCoalesce<T>(...values: Array<Optional<T>>): T {
+  return mustFind(values, doesExist);
+}