https://github.com/nichoth/pull-scan

Scan algorithm for pull streams
https://github.com/nichoth/pull-scan

Last synced: about 1 month ago
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Scan algorithm for pull streams

• Host: GitHub
• URL: https://github.com/nichoth/pull-scan
• Owner: nichoth
• Created: 2016-09-29T00:18:37.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2016-09-29T16:33:45.000Z (almost 10 years ago)
• Last Synced: 2025-08-09T13:42:08.079Z (12 months ago)
• Language: JavaScript
• Homepage: https://github.com/nichoth/pull-scan#readme
• Size: 7.81 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md

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README

          
## pull scan [![Build Status](https://travis-ci.org/nichoth/pull-scan.svg?branch=master)](https://travis-ci.org/nichoth/pull-scan)

[Scan algorithm](https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/scan.md) for pull streams. It's like reduce, but emits intermediate values. So it's more like map but with an accumulator argument.

## example

```js

var test = require('tape')

var S = require('pull-stream')

var scan = require('../')

test('works given initial state', function (t) {

    t.plan(1)

    S(

        S.values([1,2,3]),

        scan(function (acc, n) {

            return acc + n

        }, 10),

        S.collect(function (err, data) {

            t.deepEqual(data, [11,13,16], 'should use init state argument')

        })

    )

})

test('use default init state', function (t) {

    t.plan(1)

    S(

        S.values([1,2,3]),

        scan(function (acc, n) {

            return acc + n

        }),

        S.collect(function (err, data) {

            t.deepEqual(data, [1,3,6],

                'should use first val as default state')

        })

    )

})

```