push-take-until/README.md

# @push-stream-std/push-take-until

Take values from a source stream until a signal stream emits or ends.

Published as `@push-stream-std/push-take-until`.

## Synopsis

```js
import takeUntil from '@push-stream-std/push-take-until';

const signal = pushable();
const untilSignal = takeUntil(signal);

values([1, 2, 3, 4, 5]).pipe(untilSignal).pipe(collect(function (err, result) {
  console.log(result); // [1, 2] — signal ended after 2 values
}));

// End the signal stream to stop the outer stream
signal.end();
```

## Install

```bash
npm config set @push-stream-std:registry https://hub.kl1.tenere.ai/api/packages/push-stream-std/npm/
npm config set -- //hub.kl1.tenere.ai/api/packages/push-stream-std/npm/:_authToken "$PACKAGE_TOKEN"
npm install @push-stream-std/push-take-until
```

## Why
A push-stream through that passes through values from the source until the provided signal stream ends. When the signal stream ends (either normally or via abort), the take-until stream immediately ends the upstream source and downstream sink, closing the pipeline. This is useful for implementing cancellation patterns — for example, taking values from an event stream until a "stop" button is clicked.

## API

### `takeUntil(signalStream)`

Creates a take-until through stream.

- **signalStream** `object` – A push-stream source. The take-until stream pipes the signal stream to an internal sink that tracks when the signal ends. When the signal's `end()` or `abort()` fires, the take-until stream ends.
- **Returns** A through object with `pipe()`, `write()`, `end()`, `abort()`, `resume()`, `source`, `paused`, `ended`.

## Tests

```bash
npm test
```

Tests cover passthrough before signal ends, stopping after signal end, normal end without signal, signal abort propagation, and idempotent signal end handling.

## Requirements

Node.js 22 or later. ESM only.