Unstable
A simple list-like class and utilities for using it.
Usage
A collection is ordered, like an array, but its items are unique, like a set.
Globals
Constructors
Collection([array])
Creates a new collection. The collection is backed by an array.
Parameters
array : array
If array is given, it will be used as the backing array. This way the caller can fully control the collection. Otherwise a new empty array will be used, and no one but the collection will have access to it.
Functions
addCollectionProperty(object, propName, [backingArray])
Adds a collection property to the given object. Setting the property to a scalar value empties the collection and adds the value. Setting it to an array empties the collection and adds all the items in the array.
Parameters
object : object
The property will be defined on this object.
propName : string
The name of the property.
backingArray : array
If given, this will be used as the collection's backing array.
Collection
A collection object provides for...in-loop iteration. Items are yielded in the order they were added. For example, the following code...
var collection = require("sdk/util/collection");
var c = new collection.Collection();
c.add(1);
c.add(2);
c.add(3);
for (item in c)
console.log(item);
... would print this to the console:
1 2 3
Iteration proceeds over a copy of the collection made before iteration begins, so it is safe to mutate the collection during iteration; doing so does not affect the results of the iteration.
Methods
add(itemOrItems)
Adds a single item or an array of items to the collection. Any items already contained in the collection are ignored.
Parameters
itemOrItems : object
An item or array of items.
Returns
Collection : The Collection.
remove(itemOrItems)
Removes a single item or an array of items from the collection. Any items not contained in the collection are ignored.
Parameters
itemOrItems : object
An item or array of items.
Returns
Collection : The Collection.
Properties
length
The number of items in the collection array.