concurrun

Limit the number of concurrent executions of an asynchronous (promise OR cps) function

Why does this package have an average name?

https://twitter.com/KoryNunn/status/1024832220467347456

Usage with CPS

`` javascript
// Require / setup
var concurrencyLimit = require('concurrun');

var tenAtATime = concurrencyLimit(10);

// Wrap a function

var limitedReadFile = tenAtATime(require('fs').readFile);

// Call the wrapped function however you want:

for(var i = 0; i < 100; i++){
limitedReadFile('myFilePath.txt', 'utf8', function(error, file){
...
})
}

`

Usage with Promises

` javascript
// Require / setup
var concurrencyLimit = require('concurrun');

var tenAtATime = concurrencyLimit(10);

// Wrap a function

var limitedReadFile = tenAtATime.promise(require('fs/promises').readFile);

// Call the wrapped function however you want:

for(var i = 0; i < 100; i++){
limitedReadFile('myFilePath.txt', 'utf8')
.then(function(file){ ... })
.catch(function(error){ ... })
}

`

Dynamic limit

You can pass a CPS function in place of the limit to dynamically return a limit:

` javascript

// Ramp up over time
var limit = concurrencyLimit(function(info, callback){
/*
info === {
inFlight: Number of tasks currently in flight
succeeded: Number of tasks that have completed without error
complete: Number of tasks that have completed
}
*/

// Allow N in flight where N is the number of tasks that have previously finished.
callback(null, Math.max(info.complete, 1));
});
``