https://github.com/mafintosh/hyperfilter

Distributed map and filter
https://github.com/mafintosh/hyperfilter

Last synced: about 2 months ago
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Distributed map and filter

• Host: GitHub
• URL: https://github.com/mafintosh/hyperfilter
• Owner: mafintosh
• License: mit
• Created: 2016-11-03T13:51:53.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2016-11-03T14:11:53.000Z (about 8 years ago)
• Last Synced: 2024-10-16T23:37:29.383Z (about 2 months ago)
• Language: JavaScript
• Size: 4.88 KB
• Stars: 33
• Watchers: 4
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-peer-to-peer - hyperfilter
• awesome-peer-to-peer - hyperfilter

README

        
# hyperfilter

Distributed map and filter. Useful for filtering distributed streams of data,

similar to Apache Spark, but implemented in ~16 lines of code.

## Installation

```sh

$ npm install hyperfilter

```

## Usage

``` js

var hypercore = require('hypercore')

var filter = require('hyperfilter')

var memdb = require('memdb')

var core = hypercore(memdb())

var inp = core.createFeed()

var out = core.createFeed()

// uppercase all input, filter out 'hello world 1'

filter(inp, out, function (data, cb) {

  if (data.toString() === 'hello world 1') return cb()

  cb(null, data.toString().toUpperCase())

})

inp.append(new Buffer('hello world 0'))

inp.append(new Buffer('hello world 1'))

inp.append(new Buffer('hello world 2'))

out.createReadStream({live: true}).pipe(process.stdout)

// => HELLO WORLD 0

// => HELLO WORLD 2

```

## Why

We believe ops doesn't need to be complicated. If `hypercore` is distributed

streams, `hyperfilter` is a distributed filter for streams. We needed this to

to turn our feed of server logs into a feed of server errors.

## API

### filter(inputFeed, outputFeed, mapFunction(data, next))

Create a new filter function that reads data from an input `hypercore` feed to

and writes it to an output `hypercore` feed. Each chunk of data is passed

throug the `map` function. The `next` function has a signature of `err, data`.

If neither an error or data is written, it skips to the next chunk, acting like

a `filter` function.

## See Also

- https://github.com/mafintosh/hypercore

- https://github.com/mafintosh/hyperpipe

- https://github.com/mafintosh/hypername

- https://github.com/yoshuawuyts/hypertail

## License

MIT