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    util/collection

    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.

    Document Tags and Contributors

    Contributors to this page: wbamberg, jsantell, n8chz
    Last updated by: n8chz,
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