dont-collide
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
Basic usage
Use npm to install the module: ```npm install dont-collide
```
Then use dontCollide
like this:
```javascript
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
/
```
Usage where return data is returned is summed up in an array
```javascript 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
/
```
Usage where return data is provided through callback
```javascript 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
/
```
Usage for asynchronous calls
```javascript 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
/
```
Instance options
You can of course provide options for setting up dont-collide.interval
Number Default: 1 Time gap in miliseconds between each function call. ```javascript var dc = dontCollide({ interval: 1000 }); ``` This sets the interval to one call each second.finalize
Function Default: Empty function The callback function which is called when all function calls are completed. ```javascript var dc = dontCollide({ finalize: function(results) { console.log(result.correlationId + " - " + result.result); } }); ``` This sets the interval to one call each second.Throttle options
correlationId
String or number Default: 0 An id to recognize your request on. Useful if some function call takes longer than others ```javascript dc.throttle({ correlationId: 20, fn: function(){ return 'Mr. T' }}); ```fn
Function Required. The function you wish to execute with throttling ```javascript 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. ```javascript 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).asyncCallback
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. ```javascript 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 / ```callback
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. ```javascript dc.throttle({ fn: function(){ return 'Mr. T' }, callback: function(rs){ console.log(rs.result); } }); / Outputs Mr. T / ```Tests
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
License
The MIT License (MIT)
Copyright (c) 2016 Thorbjørn Gliese Jelgren (The Right Foot, www.therightfoot.dk)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.