tiny-async-pool-browser

    1.1.0 • Public • Published

    asyncPool

    Why?

    Existing solutions also re-implement Promise 😩...

    The goal of this library is to use native async functions (if ES7 is available) and/or native Promise (ES6) including Promise.race() and Promise.all() to implement the concurrency behavior (look our source code).

    What?

    asyncPool runs multiple promise-returning & async functions in a limited concurrency pool. It rejects immediately as soon as one of the promises rejects. It resolves when all the promises completes. It calls the iterator function as soon as possible (under concurrency limit). For example:

    const timeout = i => new Promise(resolve => setTimeout(() => resolve(i), i));
    await asyncPool(2, [1000, 5000, 3000, 2000], timeout);
    // Call iterator (i = 1000)
    // Call iterator (i = 5000)
    // Pool limit of 2 reached, wait for the quicker one to complete...
    // 1000 finishes
    // Call iterator (i = 3000)
    // Pool limit of 2 reached, wait for the quicker one to complete...
    // 3000 finishes
    // Call iterator (i = 2000)
    // Itaration is complete, wait until running ones complete...
    // 5000 finishes
    // 2000 finishes
    // Resolves, results are passed in given array order `[1000, 5000, 3000, 2000]`.

    Usage

    $ npm install tiny-async-pool
    
    import asyncPool from "tiny-async-pool";

    ES7 async

    const timeout = i => new Promise(resolve => setTimeout(() => resolve(i), i));
    const results = await asyncPool(2, [1000, 5000, 3000, 2000], timeout);

    Note: Something really nice will be possible soon https://github.com/tc39/proposal-async-iteration

    ES6 Promise

    const timeout = i => new Promise(resolve => setTimeout(() => resolve(i), i));
    return asyncPool(2, [1000, 5000, 3000, 2000], timeout).then(results => {
      ...
    });

    API

    asyncPool(poolLimit, array, iteratorFn)

    Runs multiple promise-returning & async functions in a limited concurrency pool. It rejects immediately as soon as one of the promises rejects. It resolves when all the promises completes. It calls the iterator function as soon as possible (under concurrency limit).

    poolLimit

    The pool limit number (>= 1).

    array

    Input array.

    iteratorFn

    Iterator function that takes two arguments (array item and the array itself). The iterator function should either return a promise or be an async function.

    License

    MIT © Rafael Xavier de Souza

    Install

    npm i tiny-async-pool-browser

    DownloadsWeekly Downloads

    1

    Version

    1.1.0

    License

    MIT

    Unpacked Size

    8.2 kB

    Total Files

    8

    Last publish

    Collaborators

    • vasilevich