Semaphore default parameters

PR-URL: #45

Author: tshemsedinov

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased][unreleased]
 
+- Semaphore default parameters
+
 ## [3.5.3][] - 2021-05-05
 
 - Implement 'toLowerCamel' and 'toUpperCamel'

lib/semaphore.js

@@ -1,7 +1,7 @@
 'use strict';
 
 class Semaphore {
-  constructor(concurrency, size, timeout) {
+  constructor(concurrency, size = 0, timeout = 0) {
     this.counter = concurrency;
     this.timeout = timeout;
     this.size = size;

test/semaphore.js

@@ -30,6 +30,29 @@ metatests.test('Semaphore', async (test) => {
   test.end();
 });
 
+metatests.test('Semaphore default', async (test) => {
+  const semaphore = new Semaphore(CONCURRENCY);
+  await semaphore.enter();
+  test.strictSame(semaphore.counter, CONCURRENCY - 1);
+  await semaphore.enter();
+  test.strictSame(semaphore.counter, CONCURRENCY - 2);
+  await semaphore.enter();
+  test.strictSame(semaphore.counter, 0);
+  try {
+    await semaphore.enter();
+  } catch (err) {
+    test.assert(err);
+  }
+  test.strictSame(semaphore.counter, 0);
+  semaphore.leave();
+  test.strictSame(semaphore.counter, CONCURRENCY - 2);
+  semaphore.leave();
+  test.strictSame(semaphore.counter, CONCURRENCY - 1);
+  semaphore.leave();
+  test.strictSame(semaphore.counter, CONCURRENCY);
+  test.end();
+});
+
 metatests.test('Semaphore timeout', async (test) => {
   const semaphore = new Semaphore(CONCURRENCY, QUEUE_SIZE, TIMEOUT);
   await semaphore.enter();

types/metautil.d.ts

@@ -55,7 +55,7 @@ export interface QueueElement {
 }
 
 export class Semaphore {
-  constructor(concurrency: number, size: number, timeout: number);
+  constructor(concurrency: number, size?: number, timeout?: number);
   counter: number;
   timeout: number;
   size: number;