# promise-postmessage

> Simple promise based post message

Latest version **3.9.0** (published 2026-08-13) · ISC license · 0 weekly downloads

## Install

```sh
npm install promise-postmessage
pnpm add promise-postmessage
yarn add promise-postmessage
bun add promise-postmessage
```

## Health

**Score 70/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; recently updated; high maintenance score; high quality score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 3.9.0 |
| Published | 2026-08-13 |
| First published | 2023-10-11 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Dependencies | 1 |
| Unpacked size | 122 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 2 |
| Author | ashubham@gmail.com |
| Maintainers | ashubham, rousan |

## Links

- npm: https://www.npmjs.com/package/promise-postmessage
- Repository: https://github.com/fabulatedev/postmessage-promise
- Homepage: https://github.com/fabulatedev/postmessage-promise#readme
- Issues: https://github.com/fabulatedev/postmessage-promise/issues
- npm.io page: https://npm.io/package/promise-postmessage

## Dependencies (1)

- [rollup](https://npm.io/package/rollup.md) ^4.0.2

## Recent versions

- 3.9.0 (latest) — 2026-08-13
- 3.8.0 — 2026-08-13
- 3.7.0 — 2026-01-21
- 3.7.0-rc.2 — 2026-01-20
- 3.7.0-rc.1 — 2026-01-20
- 3.6.0 — 2025-05-07
- 3.6.0-rc.1 — 2025-05-05
- 3.5.1 — 2024-07-16
- 3.5.0 — 2024-06-17
- 3.4.0 — 2024-06-17
- 3.3.0 — 2024-06-17
- 3.2.0 — 2024-06-14
- 3.1.1 — 2024-06-05
- 3.1.0 — 2024-06-05
- 3.0.1 — 2024-06-05
- … 11 more at https://npm.io/package/promise-postmessage/versions

## README

# postmessage-promise 
[![Coverage Status](https://coveralls.io/repos/github/fabulatedev/postmessage-promise/badge.svg?branch=main)](https://coveralls.io/github/fabulatedev/postmessage-promise?branch=main) [![npm version](https://badge.fury.io/js/promise-postmessage.svg)](https://badge.fury.io/js/promise-postmessage)

Simple promise based post message / listener.

Uses MessageChannels under the hood.

## Usage

```js
import { onMessage, sendMessage } from 'promise-postmessage';

onMessage(
    async (event) => {
        // some async operation
        const resp = await foo(event.data);
        return resp;
    }, 

    // source frame
    window.parent 
);

const resp = await sendMessage(
    // target frame window.
    document.getElementById('iframe')
        .contentWindow

    // Message payload
    { foo: 'bar' }, 
);
```

### Example: Create a simple forwarding bridge
```js
import { onMessage, sendMessage } from 'promise-postmessage';

const frame1 = document.getElementById("frame1").contentWindow;
const frame2 = window.parent; // Or could be another child iframe.

onMessage((event) => {
    return sendMessage(frame2, event.data);
}, frame1);

onMessage((event) => {
    return sendMessage(frame1, event.data);
}, frame2);
```

---
_Source: https://npm.io/package/promise-postmessage · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._