https://github.com/floatdrop/stream-assert

Assertion library for streams
https://github.com/floatdrop/stream-assert

Last synced: about 2 months ago
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Assertion library for streams

• Host: GitHub
• URL: https://github.com/floatdrop/stream-assert
• Owner: floatdrop
• Created: 2014-08-12T15:40:36.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2015-07-29T07:45:48.000Z (over 9 years ago)
• Last Synced: 2024-09-19T15:48:03.434Z (3 months ago)
• Language: JavaScript
• Size: 333 KB
• Stars: 18
• Watchers: 2
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: readme.md

Awesome Lists containing this project

• awesome-nodejs - stream-assert - Assertion library for streams. (Repository / Streams)
• awesome-nodejs-streams - floatdrop/stream-assert - Assertion library for streams (Modules)

README

        
# stream-assert

[![Build Status][travis-image]][travis-url]

Assert streams with ease.

## Usage

```js

var intoStream = require('into-stream');

var assert = require('stream-assert');

var is = require('funsert');

intoStream([1, 2, 3])

    .pipe(assert.first(is.equal(1)))

    .pipe(assert.second(is.equal(2)))

    .pipe(assert.nth(2, is.equal(3)))

    .pipe(assert.length(1))

    .pipe(assert.end(console.log));

```

## Chaining

Assertions are chained through passing `assertion` from pipe to pipe. If you want inject assertions in the middle of pipeline, you can attach `on('assertion')` handler to manualy catch assertions (instead of placing `assert.end`).

## API

### stream-assert

Builder for asserting stream.

#### nth(n, assertion)

Calls `assertion` function on `nth` element in stream.

#### first(assertion)

> alias to nth(0, obj)

#### second(assertion)

> alias to nth(1, obj)

#### last(assertion)

Calls `assertion` function on the last element in stream.

#### length(len)

Asserting, that length of stream is equal `len` at the end of the stream.

#### all(assertion)

Checking that all elements in stream pass assertion function.

#### any(assertion)

Checking that at least one of elements in stream pass assertion function.

#### end([cb])

Since streams has internal [buffer and highWatermark](http://nodejs.org/api/stream.html#stream_buffering),

that stops data flow, when reached — test stream needs a dumping point, that will flush that buffer.

`assert.end` will dump all data to `/dev/null` — so all pipes after this point will not get any data.

### assert.defaults

Type: `Object`  

Contains defaults, that will be passed to `through` constructor.

 * `highWatermark` — by default, will be equal `16`. If you don't want to use `assert.end`, then you can increase it.

## License

MIT (c) 2014 Vsevolod Strukchinsky

[travis-url]: http://travis-ci.org/floatdrop/stream-assert

[travis-image]: http://img.shields.io/travis/floatdrop/stream-assert.svg?branch=master&style=flat