it-parallel

Process incoming async(iterable) functions in parallel

About

Takes an (async) iterable that emits promise-returning functions, invokes them in parallel up to the concurrency limit and emits the results as they become available, optionally in the same order as the input

Example

import parallel from 'it-parallel'
import all from 'it-all'
import delay from 'delay'

// This can also be an iterator, async iterator, generator, etc
const input = [
  async () => {
    console.info('start 1')
    await delay(500)

    console.info('end 1')
    return 1
  },
  async () => {
    console.info('start 2')
    await delay(200)

    console.info('end 2')
    return 2
  },
  async () => {
    console.info('start 3')
    await delay(100)

    console.info('end 3')
    return 3
  }
]

const result = await all(parallel(input, {
  concurrency: 2
}))

// output:
// start 1
// start 2
// end 2
// start 3
// end 3
// end 1

console.info(result) // [2, 3, 1]

If order is important, pass ordered: true as an option:

const result = await all(parallel(input, {
  concurrency: 2,
  ordered: true
}))

// output:
// start 1
// start 2
// end 2
// start 3
// end 3
// end 1

console.info(result) // [1, 2, 3]

Install

$ npm i it-parallel

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License

Licensed under either of

• Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
• MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.