pchan

JS channels implementation... for async fun.

About

This is mt first attempt at pure JS implementation of golang style channels. The premise of channels for JS is that (in concert with ES2017 async / await and promises) they can be used to write heavily asyncronous and parallel-ish code in a very readable and pleasant way. Specifically, they allow for functions resembling threads (or goroutines) to be chained and syncronised with minimal effort.

pchan is feature complete and pretty performant, it allows for channel creation, buffering and closing, channel sends / recieves and ranging over open channels. The API is not particularly javascripty (as much a is practical, it resembles the golang API). The next attempt will just be an effort to make a channels look like more idiomatic JS.

Usage

const make = require('pchan')

const {range, close} = make

function sender(channel, data) {
  const values = [...data]

  let value
  while (value = values.shift()) {
    channel(value)
  }

  close(channel)
}

async function receiver(channel) {
  const values = []
  range(channel, value => values.push(value))

  return values
}

const chan = make(1)
const data = [1, 2, 3, 4, 5]

sender(chan, data)
receiver(chan).then(data => console.log(data))

// => '[1, 2, 3, 4, 5]'

API

make([capacity])

• capacity (number) - the size of the channels buffer (defaults to 1).

Returns a channel that will buffer capacity value(s).

channel([value])

• value (mixed) - the value to send into the channel.

sending: calling channel with value will send that value into the channel, and return a promise that resolves undefined when space for that value is available in the internal buffer.

closing: calling channel with the value null will close the channel; any subsequent sends will throw an error, but receives can continue until indefinitely, and will resolve with any remaining internally buffered values, or null if none remain.

receving: when channel is called with no arguments it will return a promise that resolves when a value from the channel's internal buffer is avaiable.

channel.close()

A convinience function used to close the channel, equivalent to channel(null).

range(channel, fn)

• channel (function) - the channel to range over.
• fn (function) - the callback function (called for each received value).

Calling range with a channel and a callback function (fn) will continue to receive from channel, passing each value to the supplied callback until the channel is closed.

License

• MIT © axdg (axdg@dfant.asia), 2107 •