Make dependencies peer. LAzy load YN so that if the feature is not used the dependency is ignored'

src/booleanConverter.ts

@@ -0,0 +1,28 @@
+import * as yn from 'yn';
+
+import { BooleanConverter, ConfigOptions } from "./types"
+
+export const booleanConverter: BooleanConverter = (options: ConfigOptions, log: (...args: any[]) => void) => {
+  const convertPredicate = (key: string): boolean => {
+    if (key) {
+      if (Array.isArray(options.convertToBoolean)) {
+        if (options.convertToBoolean.includes(key)) {
+          return true;
+        }
+      } else if (options.convertToBoolean === key) {
+        return true;
+      }
+      if (typeof options.convertToBooleanPredicate === 'function' && options.convertToBooleanPredicate(key)) {
+        return true;
+      }
+    }
+    return false;
+  }
+  Object.entries(process.env).forEach(([key, value]) => {
+    if (convertPredicate(key)) {
+      const boolValue = yn(value) ? 'true' : '';
+      process.env[key] = boolValue;
+      log('Environment variable converted into string boolean value:', key, "original:", value, 'newValue:', boolValue);
+    }
+  });
+}

src/dotenvMulti.ts

@@ -0,0 +1,46 @@
+import * as fs from 'fs';
+import * as path from 'path';
+
+import * as dotenv from 'dotenv';
+import * as dotenvExpand from 'dotenv-expand';
+
+import { BooleanConverter, ConfigOptions } from "./types"
+import { Lazy } from "./lazy"
+
+const lazyBoolConverter = new Lazy<BooleanConverter>(() => require('./booleanConverter').booleanConverter);
+
+export function config(options: ConfigOptions = {}): void {
+  const log = options.debug ? console.log : (() => {});
+
+  // Same logic as create-react-app for resolving env files
+  // https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/config/env.js
+  const NODE_ENV = (process.env.NODE_ENV || 'unknown').toLowerCase();
+  const appDirectory = fs.realpathSync(process.cwd());
+  const dotenvFilePath: string = path.resolve(appDirectory, '.env');
+
+  const dotenvFiles = [
+    `${ dotenvFilePath }.${ NODE_ENV }.local`,
+    `${ dotenvFilePath }.${ NODE_ENV }`,
+    NODE_ENV !== 'test' && `${ dotenvFilePath }.local`,
+    dotenvFilePath,
+  ].filter(i => i) as string[]; // this cast is safe due to the identity filter
+
+  log('Environment files to check:', dotenvFiles.join());
+
+  const propsConfigured = {};
+  dotenvFiles.forEach((dotenvFile) => {
+    if (fs.existsSync(dotenvFile)) {
+      const {parsed} = dotenvExpand(dotenv.config({path: dotenvFile, debug: options.debug || undefined }));
+      Object.assign(propsConfigured, parsed);
+    }
+  });
+
+  log('Environment variables loaded from dotenvs:', Object.keys(propsConfigured).length);
+  log('\t', propsConfigured);
+
+  const runBoolConverter: boolean = !!(options.convertToBooleanPredicate || options.convertToBoolean);
+  log('Environment variable boolean converter will run:', runBoolConverter);
+  if (runBoolConverter) {
+    lazyBoolConverter.get()(options, log);
+  }
+}

src/index.ts

@@ -1,69 +1,2 @@
-import * as fs from 'fs';
-import * as path from 'path';
-
-import * as dotenv from 'dotenv';
-import * as dotenvExpand from 'dotenv-expand';
-import * as yn from 'yn';
-
-export interface ConfigOptions {
-  convertToBooleanPredicate?: (variable: string) => boolean;
-  convertToBoolean?: string | string[];
-  debug?: boolean;
-}
-
-export function config(options: ConfigOptions = {}): void {
-  const log = options.debug ? console.log : (() => {});
-
-  // Same logic as create-react-app for resolving env files
-  // https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/config/env.js
-  const NODE_ENV = (process.env.NODE_ENV || 'unknown').toLowerCase();
-  const appDirectory = fs.realpathSync(process.cwd());
-  const dotenvFilePath: string = path.resolve(appDirectory, '.env');
-
-  const dotenvFiles = [
-    `${ dotenvFilePath }.${ NODE_ENV }.local`,
-    `${ dotenvFilePath }.${ NODE_ENV }`,
-    NODE_ENV !== 'test' && `${ dotenvFilePath }.local`,
-    dotenvFilePath,
-  ].filter(i => i) as string[]; // this cast is safe due to the identity filter
-
-  log('Environment files to check:', dotenvFiles.join());
-
-  const propsConfigured = {};
-  dotenvFiles.forEach((dotenvFile) => {
-    if (fs.existsSync(dotenvFile)) {
-      const {parsed} = dotenvExpand(dotenv.config({path: dotenvFile, debug: options.debug || undefined }));
-      Object.assign(propsConfigured, parsed);
-    }
-  });
-
-  log('Environment variables loaded from dotenvs:', Object.keys(propsConfigured).length);
-  log('\t', propsConfigured);
-
-  const runBoolConverter: boolean = !!(options.convertToBooleanPredicate || options.convertToBoolean);
-  log('Environment variable boolean converter will run:', runBoolConverter);
-  if (runBoolConverter) {
-    const convertPredicate = (key: string): boolean => {
-      if (key) {
-        if (Array.isArray(options.convertToBoolean)) {
-          if (options.convertToBoolean.includes(key)) {
-            return true;
-          }
-        } else if (options.convertToBoolean === key) {
-          return true;
-        }
-        if (typeof options.convertToBooleanPredicate === 'function' && options.convertToBooleanPredicate(key)) {
-          return true;
-        }
-      }
-      return false;
-    }
-    Object.entries(process.env).forEach(([key, value]) => {
-      if (convertPredicate(key)) {
-        const boolValue = yn(value) ? 'true' : '';
-        process.env[key] = boolValue;
-        log('Environment variable converted into string boolean value:', key, "original:", value, 'newValue:', boolValue);
-      }
-    });
-  }
-}
+export * from './dotenvMulti'
+export * from './types';

src/lazy.ts

@@ -0,0 +1,12 @@
+export class Lazy<T> {
+  private instance: T | undefined = undefined;
+
+  constructor(private readonly factory: () => any) {}
+
+  get (): T {
+    if (!this.instance) {
+      this.instance = this.factory();
+    }
+    return this.instance as T;
+  }
+}

src/types.ts

@@ -0,0 +1,9 @@
+export interface ConfigOptions {
+  convertToBooleanPredicate?: (variable: string) => boolean;
+  convertToBoolean?: string | string[];
+  debug?: boolean;
+}
+
+export interface BooleanConverter {
+  (options: ConfigOptions, log: (...args: any[]) => void): void;
+}