Added onProgress function and made some code refactors

.eslintrc.json

@@ -1,18 +1,26 @@
 {
-  "env": {
-    "es6": true,
-    "node": true,
-    "jest": true
-  },
-  "extends": [
-    "standard-with-typescript"
-  ],
-  "parserOptions": {
-    "project": "./tsconfig.json"
-  },
-  "rules": {
-    "@typescript-eslint/return-await": 0,
-    "@typescript-eslint/require-await": 0,
-    "@typescript-eslint/strict-boolean-expressions": 0
-  }
+	"env": {
+		"es6": true,
+		"node": true,
+		"jest": true
+	},
+	"extends": ["standard-with-typescript"],
+	"parserOptions": {
+		"project": "./tsconfig.json"
+	},
+	"rules": {
+		"semi": ["error", "always"],
+		"@typescript-eslint/semi": ["error", "always"],
+		"@typescript-eslint/indent": ["off"],
+		"@typescript-eslint/quotes": ["error", "always"],
+		"@typescript-eslint/space-before-function-paren": ["off"],
+		"@typescript-eslint/member-delimiter-style": ["off"],
+		"comma-dangle": ["off"],
+		"quotes": ["single", "always"],
+		"indent": 0,
+		"no-tabs": 0,
+		"@typescript-eslint/return-await": 0,
+		"@typescript-eslint/require-await": 0,
+		"@typescript-eslint/strict-boolean-expressions": 0
+	}
 }

.gitignore

@@ -31,3 +31,4 @@ coverage
 .vscode
 
 .vagrant
+yarn.lock

src/index.ts

@@ -1,5 +1,5 @@
-'use strict'
+'use strict';
 
-import { PromisePool } from './promise-pool'
+import { PromisePool } from './promise-pool';
 
-export = PromisePool
+export = PromisePool;

src/promise-pool-error.ts

@@ -1,59 +1,59 @@
-'use strict'
+'use strict';
 
 export class PromisePoolError<T> extends Error {
-  /**
-   * Returns the item that caused this error.
-   */
-  public item: T
-
-  /**
-   * Create a new instance for the given `message` and `item`.
-   *
-   * @param error  The original error
-   * @param item   The item causing the error
-   */
-  constructor (error: any, item: T) {
-    super()
-
-    this.item = item
-    this.name = this.constructor.name
-    this.message = this.messageFrom(error)
-
-    Error.captureStackTrace(this, this.constructor)
-  }
-
-  /**
-   * Returns a new promise pool error instance wrapping the `error` and `item`.
-   *
-   * @param {*} error
-   * @param {*} item
-   *
-   * @returns {PromisePoolError}
-   */
-  static createFrom<T>(error: any, item: T): PromisePoolError<T> {
-    return new this(error, item)
-  }
-
-  /**
-   * Returns the error message from the given `error`.
-   *
-   * @param {*} error
-   *
-   * @returns {String}
-   */
-  private messageFrom (error: any): string {
-    if (error instanceof Error) {
-      return error.message
-    }
-
-    if (typeof error === 'object') {
-      return error.message
-    }
-
-    if (typeof error === 'string' || typeof error === 'number') {
-      return error.toString()
-    }
-
-    return ''
-  }
+	/**
+	 * Returns the item that caused this error.
+	 */
+	public item: T;
+
+	/**
+	 * Create a new instance for the given `message` and `item`.
+	 *
+	 * @param error  The original error
+	 * @param item   The item causing the error
+	 */
+	constructor(error: any, item: T) {
+		super();
+
+		this.item = item;
+		this.name = this.constructor.name;
+		this.message = this.messageFrom(error);
+
+		Error.captureStackTrace(this, this.constructor);
+	}
+
+	/**
+	 * Returns a new promise pool error instance wrapping the `error` and `item`.
+	 *
+	 * @param {*} error
+	 * @param {*} item
+	 *
+	 * @returns {PromisePoolError}
+	 */
+	static createFrom<T>(error: any, item: T): PromisePoolError<T> {
+		return new this(error, item);
+	}
+
+	/**
+	 * Returns the error message from the given `error`.
+	 *
+	 * @param {*} error
+	 *
+	 * @returns {String}
+	 */
+	private messageFrom(error: any): string {
+		if (error instanceof Error) {
+			return error.message;
+		}
+
+		if (typeof error === 'object') {
+			return error.message;
+		}
+
+		if (typeof error === 'string' || typeof error === 'number') {
+			return error.toString();
+		}
+
+		return '';
+	}
 }