parallel-x v1.0.0
parallel-x
Run an array of functions in parallel
install
npm install parallel-x
usage
parallel(tasks, callback)
Run the tasks
array of functions in parallel, without waiting until the previous
function has completed. If any of the functions pass an error to its callback, the main
callback
is immediately called with the value of the error. Once the tasks
have
completed, the results are passed to the final callback
as an array.
It is also possible to use an object instead of an array. Each property will be run as a
function and the results will be passed to the final callback
as an object instead of
an array. This can be a more readable way of handling the results.
arguments
tasks
- An array or object containing functions to run. Each function is passed acallback(err, result)
which it must call on completion with an errorerr
(which can benull
) and an optionalresult
value.callback(err, results)
- An optional callback to run once all the functions have completed. This function gets a results array (or object) containing all the result arguments passed to the task callbacks.
example
const parallel = require('parallel-x')
const queue = [ 1, 2, 3, 4, 5 ]
const tasks = queue.map(v => cb => setTimeout(() => cb(null, `${v + 1}`), 500))
parallel(tasks, (err, results) => {
// the results array will equal ['2', '3', '4', '5', '6'] even though
// the second function had a shorter timeout.
})
// promisify
parallel.promise(tasks)
.then(results => {
// the results array will equal ['one','two'] even though
// the second function had a shorter timeout.
})
.catch(err => {
// error
})
This module is basically equavalent to async.parallel
, but it's
handy to just have the one function you need instead of the kitchen sink. Modularity!
Especially handy if you're serving to the browser and need to reduce your javascript
bundle size.
Works great in the browser with browserify!
license
MIT. Copyright (c) Allex Wang.
7 years ago