Promise

Install

npm install @tryghost/promise --save

or

pnpm add @tryghost/promise

Purpose

Small async utility module with pipeline, sequence, and pool helpers for Promise workflows.

Usage

const { pipeline, sequence, pool } = require('@tryghost/promise');

pipeline(tasks, ...args)

Runs tasks in order. First task receives args; each later task receives previous task's result. Promise arguments resolve before first task runs. Resolves with final task result.

const greeting = await pipeline(
    [async (userId) => ({ id: userId, name: 'Maya' }), (user) => `Hello, ${user.name}!`],
    Promise.resolve('user-123'),
);

// 'Hello, Maya!'

If a task returns an array, the next task receives the values as separate arguments:

const total = await pipeline([() => [2, 3], (left, right) => left + right]);

// 5

sequence(tasks, ...args)

Runs tasks one at time, in order. Every task receives same args. Resolves with array of results in task order. Tasks may return values or promises.

const results = await sequence(
    [async (userId) => `loaded ${userId}`, (userId) => `audited ${userId}`],
    'user-123',
);

// ['loaded user-123', 'audited user-123']

pool(tasks, maxConcurrent)

Runs task functions with at most maxConcurrent tasks active at once. Resolves with results in input order, even when tasks finish out of order. maxConcurrent must be at least 1.

const pages = await pool(
    [
        () => fetch('/api/pages/1').then((response) => response.json()),
        () => fetch('/api/pages/2').then((response) => response.json()),
        () => fetch('/api/pages/3').then((response) => response.json()),
    ],
    2,
);

// Results for pages 1, 2, and 3, in that order.

Develop

This is a mono repository, managed with Nx.

Follow the instructions for the top-level repo.

1. git clone this repo & cd into it as usual
2. Run pnpm install to install top-level dependencies.

Run

• pnpm dev

Test

• pnpm lint runs oxlint
• pnpm test runs lint and tests

Copyright & License

Copyright (c) 2013-2026 Ghost Foundation - Released under the MIT license.