Auto Purge

Automatically purge items from an array when the maxlength is hit. This module can be used in Node or the browser. Browser support is for modern ES5 browsers (IE9+, Chrome, Firefox, etc.)

Why? There are certain cases where you want a rolling array of values that are limited such as a log system or chat. Once the array fills up to the maxlength, the oldest records are purged from the array.

Getting Started

Install the AutoPurge module.

Node

npm install autopurge

var AutoPurge = require('autopurge');

Bower

bower install autopurge

Without Package Manager

Download autopurge.js or autopurge.min.js in the repository and include in your application.

Browser

<script type="text/javascript" src="path/to/autopurge.min.js"></script>

Example

var myArray = ['test', 'value', true, false, 1, 20],
    purge = new AutoPurge(10, myArray);
 
purge.push('new value'); // => 0 (no records purged)
purge.length; // => 7
purge.value; // => ['test', 'value', true, false, 1, 20, 'new value']
purge.push.apply(purge, [1, 2, 3, 4, 5]); // => 2 (records purged)
purge.value; // => [true, false, 1, 20, 'new value', 1, 2, 3, 4, 5]
 
purge.purge(2); // => [true, false]
purge.length; // => 8
 
// Array modified outside of AutoPurge?
myArray.push('modifying', 'outside', 'does', 'not', 'purge');
purge.length; // => 13 (over the maxlength!)
purge.auto(); // => [1, 20, 'new value']
purge.length; // => 3
 
purge.clear();
purge.value; // => []
purge.length; // => 0

API Documentation

Methods

AutoPurge([maxlength], [array])

Constructor function to create a new purgable array. Can be called with or without the new keyword.

Required	Argument	Type	Description
No	maxlength	Number	The maxlength the array can be. Default is 50.
No	array	Array	An external array to use. Default is [].

var purge = new AutoPurge();
var purge2 = AutoPurge(10);
var purge3 = AutoPurge(null, ['custom', 'array']);
var purge4 = new AutoPurge(10, ['custom', 'array']);

Returns AutoPurge

AutoPurge.push(...)

Push item(s) to the array. Each item should be an argument if pushing multiple items. If you need to push an array of items, use purge.push.apply(purge, [1, 2, 3, 4, 5]);.

Required	Argument	Type	Description
Yes	...	Any	Each item to push to the array as a separate argument.

purge.push('new item');
purge.push(1, 2, 'test', false);
purge.push.apply(purge, [1, 2, 3, 4, 5]);

Returns Number (the number of items purged as result of the push)

AutoPurge.purge([num])

Purge the given number of old items from the array or remove all items without resetting the _purged counter like AutoPurge.clear().

Required	Argument	Type	Description
No	num	Number/String/null	The number of items to remove, null, undefined, or 'all' to remove all items.

var purge = new AutoPurge(10, ['custom', 'array', 1, 2, 3, 4]);
purge.purge(2); // => ['custom', 'array']
 
purge.purge(); // => [1, 2, 3, 4]
purge.value; // => []
purge._purged; // => 6

Returns Array (the items purged from the array)

AutoPurge.auto()

If the array is modified without using any of the API methods, you will need to purge it. This will purge the array if the length of the array is greater than maxlength.

var arr = ['custom', 'array', 1, 2, 3, 4, true, false, {}, []],
    purge = new AutoPurge(10, arr);
 
purge.length; // => 10
arr.push('not', 'using', 'AutoPurge');
purge.length; // => 13
 
purge.auto(); // => ['custom', 'array', 1]
purge.length; // => 13

Returns Array (the items purged from the array)

AutoPurge.clear()

Clears the array and resets the _purged counter back to 0.

var purge = new AutoPurge(10, ['custom', 'array', 1, 2, 3, 4]);
purge.purge(2); // => ['custom', 'array']
purge._purged; // => 2
 
purge.clear();
purge.value; // => []
purge._purged; // => 0

Returns undefined

Properties

AutoPurge.length

Type: Number (getter)
The total length of the array.

AutoPurge.value

Type: Array (getter)
Returns the purgable array.

AutoPurge.maxlength

Type: Number
The configuration maxlength for the array.

AutoPurge._store

Type: Array
Reference to the purgable array.

AutoPurge._purged

Type: Number
The total items that have been purged from the array.

---

TODO

• Make the array observable when it's no longer "hacky" to do so.

Contributing

Want to fix a bug or implement a new feature? Submit a pull request! Before you submit the request, please follow the guidelines below:

• If you implement a new feature, write the test case for it.
• Make sure all tests pass.
• Build the minified version using grunt.
• If bumping version, update package.json, bower.json and the JS file.

License

Licensed under MIT.