Backbone Poller

Backbone poller is a small and simple utility that allows polling on any Backbone model or collection:

- Is 100% compliant with any Backbone model or collection.
- Allows you to poll without extending your base backbone models or collections
- Guarantees one poller per model/collection instance
- Supports advanced features like delayed run and exponential backoff
- Event driven to be compliant with Backbone's API
- Aborts running connections on stop/destroy
- Prevents from running conflicting requests

The annotated source code is available online.

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- Development Version 4.6kb, Uncompressed with Comments
- Production Version 1.8kb, Minified and Gzipped

----

Basic Usage:

`` javascript
// to initialize:
var poller = Backbone.Poller.get(model_or_collection);
poller.start()

// or
var poller = Backbone.Poller.get(model_or_collection).start()

// to stop:
poller.stop();
`

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` javascript
require(['path/to/backbone.poller', 'path/to/Collection'], function(Poller, Collection) {
var collection = new Collection();
var poller = Poller.get(collection).start();
});
`

Advanced Optional Options:

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` javascript
var options = {

// default delay is 1000ms
delay: 300,

// run after a delayed interval. defaults to false
// can be a boolean true to wait delay ms before starting or a number to override the wait period
delayed: 1000,

// do not stop the poller on error. defaults to false
// error event is always fired even with this option on.
continueOnError: true,

// condition for keeping polling active (when this stops being true, polling will stop)
condition: function(model){
return model.get('active') === true;
},

// We can pass data to a fetch request
data: {fields: "*", sort: "name asc"}
}
var poller = Backbone.Poller.get(model, options);
`

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in order to apply Exponential Backoff on the poller we can set the delay option as an array.
- The values are of [startDelay[, maxDelay[, multiplier]]]
- The default multiplier is 2
- The multiplier can be used as a function that gets the current delay as a parameter and returns the next one.

##### Examples:
`javascript
// basic
Backbone.Poller.get(model, {delay: [100]}).start();
// 100, 200, 400, 800, 1600, 3200 ...

// with maxDelay
Backbone.Poller.get(model, {delay: [100, 1000]}).start();
// 100, 200, 400, 800, 1000, 1000 ...

// another multiplier
Backbone.Poller.get(model, {delay: [100, 1000, 3]}).start();
// 100, 300, 900, 1000, 1000 ...

// custom multiplier function
Backbone.Poller.get(model, {
delay: [
100,
2000,
function (n) {
return n * 4
}
]
}).start();
// 100, 400, 1600, 2000, 2000 ...
`

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` javascript
var poller = Backbone.Poller.get(model);
poller.on('success', function(model){
console.info('another successful fetch!');
});
poller.on('complete', function(model){
console.info('hurray! we are done!');
});
poller.on('error', function(model){
console.error('oops! something went wrong');
});
poller.start()
`

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To stop we can manually call poller.stop() or we can make the conditional function return false:
` javascript
var poller = Backbone.Poller.get(model);
poller.stop() // manually stops the poller

var options = {
condition: function(model){
return model.get('active') === true;
}
};
var poller = Backbone.Poller.get(model, options);
model.set('active', false); // will programmatically stop the poller
`

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Stop the poller, remove all event listeners, and clear all references
`javasctipt
poller.destroy();
`

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` javascript
var isActive = poller.active() // boolean;
`

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Altering options will stop the current running poller and will require manual start.
This method removes all existing options and set the new options assigned.
` javascript
var poller = Backbone.Poller.get(model, {delay: 100}).start();

// stops the poller, replaces the options, and then starts
poller.set({delay: 300}).start();
`

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` javascript
Backbone.Poller.reset();
`

----

Change Log

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July 10th, 2017 - Diff

- Bugfix: Moved bower to be a test dependency only

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June 1st, 2015 - Diff

- Bugfix: Moved bower to be a test dependency only

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June 1st, 2015 - Diff

- Bugfix: prevent poller from being destroyed twice

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May 31, 2015 - Diff

- Added a destroy method for better garbage collection

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April 18, 2015 - Diff

- Set the delayed parameter to be a number (as well as a boolean)

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April 9, 2015 - Diff

- Better Exponential Backoff support

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Jun 24, 2014 - Diff

- Updated bower dependancies

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Jun 6, 2014 - Diff

- Added Bower support
- Added Support to node-style module.exports for browserify
- Added continueOnError option
- Added Exponential Backoff support

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Oct 28, 2013 - Diff

- Cleanup

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Sep 25, 2013 - Diff

- Added flush option to set` - defaults to false
- Moved delayed run to start function

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Jun 21, 2013 - Diff

- Bugfix: Stop pollings correctly
- Minification tweaks

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- cleanup
- delayed option bugfix
- Passing the xhr object along with the error event

----

Copyrights

Copyright (c) 2012 Uzi Kilon, Splunk Inc.

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
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.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.