@vates/generator-toolbox

Install

Installation of the npm package:

npm install --save @vates/generator-toolbox

Usage

A toolbox to ease the use of generator

Timeout

wrap a source async generator to have it throw an error when timeout is reached timeout is a positive number in milliseconds

import { Timeout } from '@vates/generator-toolbox'

const wrappedGenerator = new Timeout(sourceGenerator, timeout)

Throttle

wrap a source async generator to have it respect a max speed ( in bytes per seconds). speed is either a strictly positive number or a function returning a strictly positive number. A speed change will be used for the next emitted packet.

The source generator must yield object with a length property.

Optimized for small yields regarding to the speed, since it won't split incoming packet.

If the generator reached the max speed it will be paused, limiting memory consumption.

import { Throttle } from '@vates/generator-toolbox'

const wrappedGenerator = new Throttle(sourceGenerator, speed)

Synchronized

Fork a generator. The rules are:

• if the source returns, all the forks return
• if the forks error, all the forks error with the same error
• if a fork returns, it is stopped, but the generator continue with the other
• if a fork errors, it is stopped, but the generator continue with the other
• if all the forks return, the source is stopped
• if all the forks error, the source is errored with the last error
• the source start producing a packet when the fastest forked ask for it
• the source forks get the packet only when all the forks asked for it, no buffer stores in memory

import { Synchronized } from '@vates/generator-toolbox'

async function consume(generator: AsyncGenerator) {
  for await (const val of generator) {
    console.log({ val })
  }
}
const forker = new Synchronized(generator)
const first = forker.fork('first')
const second = forker.fork('second')
await Promise.all([consume(first), consume(second)])

Note: you can stop early a generator by calling generator.return(), and you can stop in in error by calling generator.throw(error)

Contributions

Contributions are very welcomed, either on the documentation or on the code.

You may:

• report any issue you've encountered;
• fork and create a pull request.

License

MIT © Vates SAS