A throttle for functions that calls external sources. Developed in order to prevent "Connection refused" errors.
Use it to prevent collisions and "denial of service" when sending data in a loop to an external source.
- Easy to use and fast to implement
- Ultra lightweight
- Option to return function data as an array when finished or to return data for every call
- Suppport for returning data through asyncronous callbacks
Use npm to install the module:
npm install dont-collide
Then use dontCollide
like this:
var dontCollide = require('dont-collide');
var dc = dontCollide();
dc.throttle(
function(p1, p2, p3) {
console.log('Fired: ' + p1 + ' - ' + p2 + ' - ' + p3);
}
,1,2,3);
/*
Outputs
Fired: 1 - 2 - 3
*/
var dontCollide = require('dont-collide');
let cb = function(results) {
for(var i = 0; i < results.length; i++){
console.log("CorrelationId: " + results[i].correlationId + "\nResult: " + results[i].result + "\n\n");
}
}
var dc = dontCollide({ finalize: cb });
dc.throttle({ correlationId: 20, fn: function(){ return 'Mr. T' }});
dc.throttle({ correlationId: 30, fn: function(){ return 'Face' }});
dc.throttle({ correlationId: 40, fn: function(){ return 'Hannibal' }});
/*
Outputs:
CorrelationId: 20
Result: Mr. T
CorrelationId: 30
Result: Face
CorrelationId: 40
Result: Hannibal
*/
var dontCollide = require('dont-collide');
let cb = (result) => {
console.log("CorrelationId: " + result.correlationId + "\nResult: " + result.result + "\n\n");
}
var dc = dontCollide();
dc.throttle({ correlationId: 20, fn: function(){ return 'Mr. T' }, callback: cb});
dc.throttle({ correlationId: 30, fn: function(){ return 'Face' }, callback: cb});
dc.throttle({ correlationId: 40, fn: function(){ return 'Hannibal' }, callback: cb});
/*
Outputs:
CorrelationId: 20
Result: Mr. T
CorrelationId: 30
Result: Face
CorrelationId: 40
Result: Hannibal
*/
var dontCollide = require('dont-collide');
let cb = function(greeting, cid, rs) {
console.log(cid + ": " + greeting + " " + rs);
}
const dc = dontCollide();
dc.throttle({ correlationId: 20, fn: function(greeting, cid, c) { setTimeout(() => { c(greeting, cid, 'Mr. T'); }, 1 ); }, asyncCallback: cb }, 'Hi');
dc.throttle({ correlationId: 30, fn: function(greeting, cid, c) { setTimeout(() => { c(greeting, cid, 'Hannibal'); }, 100 ); }, asyncCallback: cb}, 'Hello');
dc.throttle({ correlationId: 40, fn: function(greeting, cid, c) { setTimeout(() => { c(greeting, cid, 'Face'); }, 50 ); }, asyncCallback: cb}, 'Good day');
/*
Outputs:
20: Hi Mr. T
40: Good day Face
30: Hello Hannibal
*/
You can of course provide options for setting up dont-collide.
Number
Default: 1
Time gap in miliseconds between each function call.
var dc = dontCollide({ interval: 1000 });
This sets the interval to one call each second.
Function
Default: Empty function
The callback function which is called when all function calls are completed.
var dc = dontCollide({ finalize: function(results) { console.log(result.correlationId + " - " + result.result); } });
This sets the interval to one call each second.
String or number
Default: 0
An id to recognize your request on. Useful if some function call takes longer than others
dc.throttle({ correlationId: 20, fn: function(){ return 'Mr. T' }});
Function
Required.
The function you wish to execute with throttling
dc.throttle({ fn: function(num1, num2){ console.log(num1 + num2) }}, 5, 10);
/*
Outputs
15
*/
Actually, if you don't wish to set any other options, you can just send the function alone.
dc.throttle(function(num1, num2){ console.log(num1 + num2) }, 5, 10);
/*
Outputs
15
*/
You can always pass parameters by sending a parameter list after the options (or your function).
Function
Default: null
When using asyncCallback two more parameters are added to the parameter list of your function call. The correlationId and the async callback.
dc.throttle({ correlationId: 40, fn: function(greeting, cid, c) { setTimeout(() => { c(greeting, cid, 'Face'); }, 50 ); }, asyncCallback: function(greeting, cid, rs){console.log(cid + ": " + greeting + " " + rs);}}, 'Good day');
/*
Outputs
30: Hello Hannibal
*/
Function
Default: null
A function that is called with the result for every execution. If this is set for a call to throttle, then the result will not go into the results that is send to the finalize function.
dc.throttle({ fn: function(){ return 'Mr. T' }, callback: function(rs){ console.log(rs.result); } });
/*
Outputs
Mr. T
*/
To run tests on this module, make sure that the modules for the tests are installed
npm install dont-collide --dev
Then run:
npm test
#Release notes
- 1.0.1 - Changed default finalize prop from arrow function to function.
- 1.0.0 - First working version
#Keywords
- throttle
- throttling
- function queue
- method queue
- queue
- dont-collide
The MIT License (MIT)
Copyright (c) 2016 Thorbjørn Gliese Jelgren (The Right Foot, www.therightfoot.dk)
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