Run an array of functions in parallel, but limit the number of tasks executing at the same time
npm install run-parallel-limit[travis-image]: https://img.shields.io/travis/feross/run-parallel-limit/master.svg
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!run-parallel-limit 
```
npm install run-parallel-limit
#### parallelLimit(tasks, limit, [callback])
Run the tasks array of functions in parallel, with a maximum of limit tasks executingcallback
at the same time. If any of the functions pass an error to its callback, the main is immediately called with the value of the error. Once the tasks havecallback
completed, the results are passed to the final as an array.
Note that the tasks are not executed in batches, so there is no guarantee that the firstlimit tasks will complete before any others are started.
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 error err (which cannull
be ) and an optional result value.limit
- - The maximum number of tasks to run at any time.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
`js
var parallelLimit = require('run-parallel-limit')
var tasks = [
function (callback) {
setTimeout(function () {
callback(null, 'one')
}, 200)
},
function (callback) {
setTimeout(function () {
callback(null, 'two')
}, 100)
},
... hundreds more tasks ...
]
parallelLimit(tasks, 5, function (err, results) {
// optional callback
// the results array will equal ['one', 'two', ...] even though
// the second function had a shorter timeout.
})
`
The above code runs with a concurrency limit of 5, so at most 5 tasks will be running at
any given time.
This module is basically equavalent to
async.parallelLimit`,
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!
- run-auto
- run-parallel
- run-series
- run-waterfall
MIT. Copyright (c) Feross Aboukhadijeh.