/**
* Collection utilities beyond what is provided in the YUI core
* @module collection
* @submodule arraylist
*/
var YArray = Y.Array,
YArray_each = YArray.each,
ArrayListProto;
/**
* Generic ArrayList class for managing lists of items and iterating operations
* over them. The targeted use for this class is for augmentation onto a
* class that is responsible for managing multiple instances of another class
* (e.g. NodeList for Nodes). The recommended use is to augment your class with
* ArrayList, then use ArrayList.addMethod to mirror the API of the constituent
* items on the list's API.
*
* The default implementation creates immutable lists, but mutability can be
* provided via the arraylist-add submodule or by implementing mutation methods
* directly on the augmented class's prototype.
*
* @class ArrayList
* @constructor
* @param items { Array } array of items this list will be responsible for
*/
function ArrayList( items ) {
if ( items !== undefined ) {
this._items = Y.Lang.isArray( items ) ? items : YArray( items );
} else {
// ||= to support lazy initialization from augment
this._items = this._items || [];
}
}
ArrayListProto = {
/**
* Get an item by index from the list. Override this method if managing a
* list of objects that have a different public representation (e.g. Node
* instances vs DOM nodes). The iteration methods that accept a user
* function will use this method for access list items for operation.
*
* @method item
* @param i { Integer } index to fetch
* @return { mixed } the item at the requested index
*/
item: function ( i ) {
return this._items[i];
},
/**
* <p>Execute a function on each item of the list, optionally providing a
* custom execution context. Default context is the item.</p>
*
* <p>The callback signature is <code>callback( item, index )</code>.</p>
*
* @method each
* @param fn { Function } the function to execute
* @param context { mixed } optional override 'this' in the function
* @return { ArrayList } this instance
* @chainable
*/
each: function ( fn, context ) {
YArray_each( this._items, function ( item, i ) {
item = this.item( i );
fn.call( context || item, item, i, this );
}, this);
return this;
},
/**
* <p>Execute a function on each item of the list, optionally providing a
* custom execution context. Default context is the item.</p>
*
* <p>The callback signature is <code>callback( item, index )</code>.</p>
*
* <p>Unlike <code>each</code>, if the callback returns true, the
* iteratation will stop.</p>
*
* @method some
* @param fn { Function } the function to execute
* @param context { mixed } optional override 'this' in the function
* @return { Boolean } True if the function returned true on an item
*/
some: function ( fn, context ) {
return YArray.some( this._items, function ( item, i ) {
item = this.item( i );
return fn.call( context || item, item, i, this );
}, this);
},
/**
* Finds the first index of the needle in the managed array of items.
*
* @method indexOf
* @param needle { mixed } The item to search for
* @return { Integer } Array index if found. Otherwise -1
*/
indexOf: function ( needle ) {
return YArray.indexOf( this._items, needle );
},
/**
* How many items are in this list?
*
* @method size
* @return { Integer } Number of items in the list
*/
size: function () {
return this._items.length;
},
/**
* Is this instance managing any items?
*
* @method isEmpty
* @return { Boolean } true if 1 or more items are being managed
*/
isEmpty: function () {
return !this.size();
},
/**
* Provides an array-like representation for JSON.stringify.
*
* @method toJSON
* @return { Array } an array representation of the ArrayList
*/
toJSON: function () {
return this._items;
}
};
// Default implementation does not distinguish between public and private
// item getter
/**
* Protected method for optimizations that may be appropriate for API
* mirroring. Similar in functionality to <code>item</code>, but is used by
* methods added with <code>ArrayList.addMethod()</code>.
*
* @method _item
* @protected
* @param i { Integer } Index of item to fetch
* @return { mixed } The item appropriate for pass through API methods
*/
ArrayListProto._item = ArrayListProto.item;
// Mixed onto existing proto to preserve constructor NOT being an own property.
// This has bitten me when composing classes by enumerating, copying prototypes.
Y.mix(ArrayList.prototype, ArrayListProto);
Y.mix( ArrayList, {
/**
* <p>Adds a pass through method to dest (typically the prototype of a list
* class) that calls the named method on each item in the list with
* whatever parameters are passed in. Allows for API indirection via list
* instances.</p>
*
* <p>Accepts a single string name or an array of string names.</p>
*
* <pre><code>list.each( function ( item ) {
* item.methodName( 1, 2, 3 );
* } );
* // becomes
* list.methodName( 1, 2, 3 );</code></pre>
*
* <p>Additionally, the pass through methods use the item retrieved by the
* <code>_item</code> method in case there is any special behavior that is
* appropriate for API mirroring.</p>
*
* <p>If the iterated method returns a value, the return value from the
* added method will be an array of values with each value being at the
* corresponding index for that item. If the iterated method does not
* return a value, the added method will be chainable.
*
* @method addMethod
* @static
* @param dest {Object} Object or prototype to receive the iterator method
* @param name {String|String[]} Name of method of methods to create
*/
addMethod: function ( dest, names ) {
names = YArray( names );
YArray_each( names, function ( name ) {
dest[ name ] = function () {
var args = YArray( arguments, 0, true ),
ret = [];
YArray_each( this._items, function ( item, i ) {
item = this._item( i );
var result = item[ name ].apply( item, args );
if ( result !== undefined && result !== item ) {
ret[i] = result;
}
}, this);
return ret.length ? ret : this;
};
} );
}
} );
Y.ArrayList = ArrayList;
