nodejs promise queue

promise-queue.js

class PromiseQueue {
    constructor(tasks = []) {
        this.task = Promise.resolve();
        for (const { func, args } of tasks) {
            this.run(func, ...args);
        }
    }

    run(func, ...args) {
        return new Promise((resolve, reject) => {
            this.task = this.task.then(async () => {
                try {
                    const response = await func(...args);
                    resolve(response);
                } catch (error) {
                    reject(error);
                }
                return Promise.resolve();
            });
        });
    }

    all() {
        return this.task;
    }
}

(async function () {

    const results = [];
    function usingConstructor() {
        const queue = new PromiseQueue([
            { func: printDelayed, args: ['first', 500] },
            { func: printDelayed, args: ['second', 400] },
            { func: printDelayed, args: ['third', 300] },
            { func: d => Promise.reject(d), args: ['failed'] },
            { func: printDelayed, args: ['fourth', 200] },
            { func: printDelayed, args: ['fifth', 100] },
        ]);
        return queue;
    }

    function usingFunction() {
        const queue = new PromiseQueue();
        queue.run(printDelayed, 'first', 500);
        queue.run(printDelayed, 'second', 400);
        queue.run(printDelayed, 'third', 300);
        queue.run(d => Promise.reject(d), 'failed').catch(e => results.push(e));
        queue.run(printDelayed, 'fourth', 200);
        queue.run(printDelayed, 'fifth', 100);
        return queue;
    }

    const queue = usingFunction();

    function printDelayed(message, delay) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                console.log(message);
                results.push(message);
                resolve(message);
            }, delay);
        });
    }

    await queue.all();

    console.log('results', results);
})();