8000 Async Pool with await/await and timeout · HowProgrammingWorks/Pool@e7723ea · GitHub
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tshemsedinovtshemsedinov
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Async Pool with await/await and timeout
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‎JavaScript/a-await.js

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'use strict';
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class Pool {
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constructor() {
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this.items = [];
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this.free = [];
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this.queue = [];
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this.current = 0;
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this.size = 0;
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this.available = 0;
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}
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async next() {
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if (this.size === 0) return null;
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if (this.available === 0) {
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return new Promise((resolve) => {
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this.queue.push(resolve);
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});
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}
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let item = null;
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let free = false;
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do {
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item = this.items[this.current];
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free = this.free[this.current];
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this.current++;
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} while (!item || !free);
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if (this.current === this.size) this.current = 0;
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return item;
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}
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add(item) {
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if (this.items.includes(item)) throw new Error('Pool: add duplicates');
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this.size++;
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this.available++;
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this.items.push(item);
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this.free.push(true);
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}
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async capture() {
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const item = await this.next();
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if (!item) return null;
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const index = this.items.indexOf(item);
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this.free[index] = false;
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this.available--;
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return item;
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}
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release(item) {
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const index = this.items.indexOf(item);
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if (index < 0) throw new Error('Pool: release unexpected item');
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if (this.free[index]) throw new Error('Pool: release not captured');
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this.free[index] = true;
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this.available++;
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if (this.queue.length > 0) {
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const resolve = this.queue.shift();
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if (resolve) setTimeout(resolve, 0, item);
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}
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}
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}
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// Usage
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(async () => {
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const pool = new Pool();
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pool.add({ item: 1 });
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pool.add({ item: 2 });
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const last = { item: 3 };
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pool.add(last);
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const x1 = await pool.capture();
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console.log({ x1 });
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const x2 = await pool.capture();
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console. 57AE log({ x2 });
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const x3 = await pool.capture();
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console.log({ x3 });
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pool.capture().then((x4) => {
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console.log({ x4 });
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});
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pool.capture().then((x5) => {
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console.log({ x5 });
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});
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pool.capture().then((x6) => {
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console.log({ x6 });
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});
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pool.release(x2);
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pool.release(x1);
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pool.release(x3);
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})();

‎JavaScript/b-timeout.js

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'use strict';
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class Pool {
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constructor(options = {}) {
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this.items = [];
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this.free = [];
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this.queue = [];
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this.timeout = options.timeout || 0;
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this.current = 0;
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this.size = 0;
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this.available = 0;
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}
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async next() {
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if (this.size === 0) return null;
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if (this.available === 0) {
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return new Promise((resolve, reject) => {
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const waiting = { resolve, timer: null };
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waiting.timer = setTimeout(() => {
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waiting.resolve = null;
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this.queue.shift();
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reject(new Error('Pool next item timeout'));
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}, this.timeout);
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this.queue.push(waiting);
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});
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}
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let item = null;
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let free = false;
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do {
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item = this.items[this.current];
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free = this.free[this.current];
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this.current++;
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} while (!item || !free);
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if (this.current === this.size) this.current = 0;
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return item;
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}
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add(item) {
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if (this.items.includes(item)) throw new Error('Pool: add duplicates');
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this.size++;
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this.available++;
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this.items.push(item);
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this.free.push(true);
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}
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async capture() {
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const item = await this.next();
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if (!item) return null;
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const index = this.items.indexOf(item);
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this.free[index] = false;
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this.available--;
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return item;
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}
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release(item) {
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const index = this.items.indexOf(item);
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if (index < 0) throw new Error('Pool: release unexpected item');
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if (this.free[index]) throw new Error('Pool: release not captured');
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this.free[index] = true;
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this.available++;
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if (this.queue.length > 0) {
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const { resolve, timer } = this.queue.shift();
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clearTimeout(timer);
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if (resolve) setTimeout(resolve, 0, item);
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}
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}
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}
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// Usage
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(async () => {
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const pool = new Pool({ timeout: 5000 });
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pool.add({ item: 1 });
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pool.add({ item: 2 });
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const last = { item: 3 };
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pool.add(last);
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const x1 = await pool.capture();
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console.log({ x1 });
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const x2 = await pool.capture();
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console.log({ x2 });
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const x3 = await pool.capture();
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console.log({ x3 });
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pool.capture().then((x4) => {
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console.log({ x4 });
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});
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pool.capture().then((x5) => {
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console.log({ x5 });
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});
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pool.capture().then((x6) => {
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console.log({ x6 });
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}).catch((err) => {
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console.error({ err });
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});
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pool.release(x2);
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pool.release(x1);
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setTimeout(() => {
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pool.release(x3);
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}, 3000);
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})();

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