diff --git a/docs/api/salty-dog.main.md b/docs/api/salty-dog.main.md
deleted file mode 100644
index 68f4199..0000000
--- a/docs/api/salty-dog.main.md
+++ /dev/null
@@ -1,22 +0,0 @@
-<!-- Do not edit this file. It is automatically generated by API Documenter. -->
-
-[Home](./index.md) &gt; [salty-dog](./salty-dog.md) &gt; [main](./salty-dog.main.md)
-
-## main() function
-
-<b>Signature:</b>
-
-```typescript
-export declare function main(argv: Array<string>): Promise<number>;
-```
-
-## Parameters
-
-|  Parameter | Type | Description |
-|  --- | --- | --- |
-|  argv | <code>Array&lt;string&gt;</code> |  |
-
-<b>Returns:</b>
-
-`Promise<number>`
-
diff --git a/docs/api/salty-dog.md b/docs/api/salty-dog.md
index 72684c9..f83d612 100644
--- a/docs/api/salty-dog.md
+++ b/docs/api/salty-dog.md
@@ -4,9 +4,3 @@
 
 ## salty-dog package
 
-## Functions
-
-|  Function | Description |
-|  --- | --- |
-|  [main(argv)](./salty-dog.main.md) |  |
-
diff --git a/src/app.ts b/src/app.ts
new file mode 100644
index 0000000..4329cb7
--- /dev/null
+++ b/src/app.ts
@@ -0,0 +1,83 @@
+import { createLogger } from 'bunyan';
+import { showCompletionScript } from 'yargs';
+
+import { loadConfig } from './config';
+import { CONFIG_ARGS_NAME, CONFIG_ARGS_PATH, MODE, parseArgs, VALID_MODES } from './config/args';
+import { YamlParser } from './parser/YamlParser';
+import { createRuleSelector, createRuleSources, loadRules, resolveRules, visitRules } from './rule';
+import { loadSource, writeSource } from './source';
+import { VERSION_INFO } from './version';
+import { VisitorContext } from './visitor/VisitorContext';
+
+const STATUS_SUCCESS = 0;
+const STATUS_ERROR = 1;
+const STATUS_MAX = 255;
+
+export async function main(argv: Array<string>): Promise<number> {
+  const { args, mode } = await parseArgs(argv);
+  if (mode === MODE.complete) {
+    showCompletionScript();
+    return STATUS_SUCCESS;
+  }
+
+  const config = await loadConfig(args[CONFIG_ARGS_NAME], ...args[CONFIG_ARGS_PATH]);
+
+  const logger = createLogger(config.data.logger);
+  logger.info(VERSION_INFO, 'version info');
+  logger.info({ args, mode }, 'main arguments');
+
+  // check mode
+  if (!VALID_MODES.has(mode)) {
+    logger.error({ mode }, 'unsupported mode');
+    return STATUS_ERROR;
+  }
+
+  const ctx = new VisitorContext({
+    innerOptions: {
+      coerce: args.coerce,
+      defaults: args.defaults,
+      mutate: mode === MODE.fix,
+    },
+    logger,
+  });
+
+  const ruleSelector = createRuleSelector(args);
+  const ruleSources = createRuleSources(args);
+
+  const loadedRules = await loadRules(ruleSources, ctx);
+  const activeRules = await resolveRules(loadedRules, ruleSelector);
+
+  if (mode === MODE.list) {
+    logger.info({
+      activeCount: activeRules.length,
+      activeRules,
+      loadedCount: loadedRules.length,
+      loadedRules,
+      ruleSelector,
+      ruleSources,
+    }, 'listing active rules');
+    return STATUS_SUCCESS;
+  }
+
+  const parser = new YamlParser();
+  const source = await loadSource(args.source);
+  const docs = parser.parse(source);
+
+  for (const data of docs) {
+    await visitRules(ctx, activeRules, data);
+  }
+
+  if (ctx.errors.length === 0) {
+    logger.info('all rules passed');
+    const output = parser.dump(...docs);
+    await writeSource(args.dest, output);
+    return STATUS_SUCCESS;
+  }
+
+  logger.error({ count: ctx.errors.length, errors: ctx.errors }, 'some rules failed');
+  if (args.count) {
+    return Math.min(ctx.errors.length, STATUS_MAX);
+  }
+
+  return STATUS_ERROR;
+}
diff --git a/src/index.ts b/src/index.ts
index ca0d94b..154ca87 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,89 +1,12 @@
-import { createLogger } from 'bunyan';
-import { showCompletionScript } from 'yargs';
+import { main } from './app';
 
-import { loadConfig } from './config';
-import { CONFIG_ARGS_NAME, CONFIG_ARGS_PATH, MODE, parseArgs, VALID_MODES } from './config/args';
-import { YamlParser } from './parser/YamlParser';
-import { createRuleSelector, createRuleSources, loadRules, resolveRules, visitRules } from './rule';
-import { loadSource, writeSource } from './source';
-import { VERSION_INFO } from './version';
-import { VisitorContext } from './visitor/VisitorContext';
-
-const STATUS_SUCCESS = 0;
 const STATUS_ERROR = 1;
-const STATUS_MAX = 255;
 
-export async function main(argv: Array<string>): Promise<number> {
-  const { args, mode } = await parseArgs(argv);
-  if (mode === MODE.complete) {
-    showCompletionScript();
-    return STATUS_SUCCESS;
-  }
-
-  const config = await loadConfig(args[CONFIG_ARGS_NAME], ...args[CONFIG_ARGS_PATH]);
-
-  const logger = createLogger(config.data.logger);
-  logger.info(VERSION_INFO, 'version info');
-  logger.info({ args, mode }, 'main arguments');
-
-  // check mode
-  if (!VALID_MODES.has(mode)) {
-    logger.error({ mode }, 'unsupported mode');
-    return STATUS_ERROR;
-  }
-
-  const ctx = new VisitorContext({
-    innerOptions: {
-      coerce: args.coerce,
-      defaults: args.defaults,
-      mutate: mode === MODE.fix,
-    },
-    logger,
-  });
-
-  const ruleSelector = createRuleSelector(args);
-  const ruleSources = createRuleSources(args);
-
-  const loadedRules = await loadRules(ruleSources, ctx);
-  const activeRules = await resolveRules(loadedRules, ruleSelector);
-
-  if (mode === MODE.list) {
-    logger.info({
-      activeCount: activeRules.length,
-      activeRules,
-      loadedCount: loadedRules.length,
-      loadedRules,
-      ruleSelector,
-      ruleSources,
-    }, 'listing active rules');
-    return STATUS_SUCCESS;
-  }
-
-  const parser = new YamlParser();
-  const source = await loadSource(args.source);
-  const docs = parser.parse(source);
-
-  for (const data of docs) {
-    await visitRules(ctx, activeRules, data);
-  }
-
-  if (ctx.errors.length === 0) {
-    logger.info('all rules passed');
-    const output = parser.dump(...docs);
-    await writeSource(args.dest, output);
-    return STATUS_SUCCESS;
-  }
-
-  logger.error({ count: ctx.errors.length, errors: ctx.errors }, 'some rules failed');
-  if (args.count) {
-    return Math.min(ctx.errors.length, STATUS_MAX);
-  }
-
-  return STATUS_ERROR;
-}
-
-main(process.argv).then((status) => process.exit(status)).catch((err) => {
-  /* eslint-disable-next-line no-console */
+/**
+ * This is the main entry-point to the program and the only file not included in the main bundle.
+ */
+main(process.argv).then((status) => process.exit(status)).catch((err: Error) => {
+  // eslint-disable-next-line no-console
   console.error('uncaught error during main:', err);
   process.exit(STATUS_ERROR);
 });