wp-api.js

(function( window, undefined ) {

	'use strict';

	function WP_API() {
		this.models = {};
		this.collections = {};
		this.views = {};
	}

	window.wp            = window.wp || {};
	wp.api               = wp.api || new WP_API();
	wp.api.versionString = wp.api.versionString || 'wp/v2/';

	// Alias _includes to _.contains, ensuring it is available.
	if ( ! _.isFunction( _.includes ) && _.isFunction( _.contains ) ) {
	  _.includes = _.contains;
	}

})( window );

(function( window, undefined ) {

	'use strict';

	var pad, r;

	window.wp = window.wp || {};
	wp.api = wp.api || {};
	wp.api.utils = wp.api.utils || {};

	/**
	 * ECMAScript 5 shim, adapted from MDN.
	 * @link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString
	 */
	if ( ! Date.prototype.toISOString ) {
		pad = function( number ) {
			r = String( number );
			if ( 1 === r.length ) {
				r = '0' + r;
			}

			return r;
		};

		Date.prototype.toISOString = function() {
			return this.getUTCFullYear() +
				'-' + pad( this.getUTCMonth() + 1 ) +
				'-' + pad( this.getUTCDate() ) +
				'T' + pad( this.getUTCHours() ) +
				':' + pad( this.getUTCMinutes() ) +
				':' + pad( this.getUTCSeconds() ) +
				'.' + String( ( this.getUTCMilliseconds() / 1000 ).toFixed( 3 ) ).slice( 2, 5 ) +
				'Z';
		};
	}

	/**
	 * Parse date into ISO8601 format.
	 *
	 * @param {Date} date.
	 */
	wp.api.utils.parseISO8601 = function( date ) {
		var timestamp, struct, i, k,
			minutesOffset = 0,
			numericKeys = [ 1, 4, 5, 6, 7, 10, 11 ];

		// ES5 §15.9.4.2 states that the string should attempt to be parsed as a Date Time String Format string
		// before falling back to any implementation-specific date parsing, so that’s what we do, even if native
		// implementations could be faster.
		//              1 YYYY                2 MM       3 DD           4 HH    5 mm       6 ss        7 msec        8 Z 9 ±    10 tzHH    11 tzmm
		if ( ( struct = /^(\d{4}|[+\-]\d{6})(?:-(\d{2})(?:-(\d{2}))?)?(?:T(\d{2}):(\d{2})(?::(\d{2})(?:\.(\d{3}))?)?(?:(Z)|([+\-])(\d{2})(?::(\d{2}))?)?)?$/.exec( date ) ) ) {

			// Avoid NaN timestamps caused by “undefined” values being passed to Date.UTC.
			for ( i = 0; ( k = numericKeys[i] ); ++i ) {
				struct[k] = +struct[k] || 0;
			}

			// Allow undefined days and months.
			struct[2] = ( +struct[2] || 1 ) - 1;
			struct[3] = +struct[3] || 1;

			if ( 'Z' !== struct[8]  && undefined !== struct[9] ) {
				minutesOffset = struct[10] * 60 + struct[11];

				if ( '+' === struct[9] ) {
					minutesOffset = 0 - minutesOffset;
				}
			}

			timestamp = Date.UTC( struct[1], struct[2], struct[3], struct[4], struct[5] + minutesOffset, struct[6], struct[7] );
		} else {
			timestamp = Date.parse ? Date.parse( date ) : NaN;
		}

		return timestamp;
	};

	/**
	 * Helper function for getting the root URL.
	 * @return {[type]} [description]
	 */
	wp.api.utils.getRootUrl = function() {
		return window.location.origin ?
			window.location.origin + '/' :
			window.location.protocol + '/' + window.location.host + '/';
	};

	/**
	 * Helper for capitalizing strings.
	 */
	wp.api.utils.capitalize = function( str ) {
		if ( _.isUndefined( str ) ) {
			return str;
		}
		return str.charAt( 0 ).toUpperCase() + str.slice( 1 );
	};

	/**
	 * Extract a route part based on negitive index.
	 *
	 * @param {string} route The endpoint route.
	 * @param {int}    part  The number of parts from the end of the route to retrieve. Default 1.
	 *                       Example route `/a/b/c`: part 1 is `c`, part 2 is `b`, part 3 is `a`.
	 */
	wp.api.utils.extractRoutePart = function( route, part ) {
		var routeParts;

		part  = part || 1;

		// Remove versions string from route to avoid returning it.
		route = route.replace( wp.api.versionString, '' );
		routeParts = route.split( '/' ).reverse();
		if ( _.isUndefined( routeParts[ --part ] ) ) {
			return '';
		}
		return routeParts[ part ];
	};

	/**
	 * Extract a parent name from a passed route.
	 *
	 * @param {string} route The route to extract a name from.
	 */
	wp.api.utils.extractParentName = function( route ) {
		var name,
			lastSlash = route.lastIndexOf( '_id>[\\d]+)/' );

		if ( lastSlash < 0 ) {
			return '';
		}
		name = route.substr( 0, lastSlash - 1 );
		name = name.split( '/' );
		name.pop();
		name = name.pop();
		return name;
	};

	/**
	 * Add args and options to a model prototype from a route's endpoints.
	 *
	 * @param {array}  routeEndpoints Array of route endpoints.
	 * @param {Object} modelInstance  An instance of the model (or collection)
	 *                                to add the args to.
	 */
	wp.api.utils.decorateFromRoute = function( routeEndpoints, modelInstance ) {

		/**
		 * Build the args based on route endpoint data.
		 */
		_.each( routeEndpoints, function( routeEndpoint ) {

			// Add post and edit endpoints as model args.
			if ( _.includes( routeEndpoint.methods, 'POST' ) || _.includes( routeEndpoint.methods, 'PUT' ) ) {

				// Add any non empty args, merging them into the args object.
				if ( ! _.isEmpty( routeEndpoint.args ) ) {

					// Set as defauls if no args yet.
					if ( _.isEmpty( modelInstance.prototype.args ) ) {
						modelInstance.prototype.args = routeEndpoint.args;
					} else {

						// We already have args, merge these new args in.
						modelInstance.prototype.args = _.union( routeEndpoint.args, modelInstance.prototype.defaults );
					}
				}
			} else {

				// Add GET method as model options.
				if ( _.includes( routeEndpoint.methods, 'GET' ) ) {

					// Add any non empty args, merging them into the defaults object.
					if ( ! _.isEmpty( routeEndpoint.args ) ) {

						// Set as defauls if no defaults yet.
						if ( _.isEmpty( modelInstance.prototype.options ) ) {
							modelInstance.prototype.options = routeEndpoint.args;
						} else {

							// We already have options, merge these new args in.
							modelInstance.prototype.options = _.union( routeEndpoint.args, modelInstance.prototype.options );
						}
					}

				}
			}

		} );

	};

	/**
	 * Add mixins and helpers to models depending on their defaults.
	 *
	 * @param {Backbone Model} model          The model to attach helpers and mixins to.
	 * @param {string}         modelClassName The classname of the constructed model.
	 * @param {Object} 	       loadingObjects An object containing the models and collections we are building.
	 */
	wp.api.utils.addMixinsAndHelpers = function( model, modelClassName, loadingObjects ) {

		var hasDate = false,

			/**
			 * Array of parseable dates.
			 *
			 * @type {string[]}.
			 */
			parseableDates = [ 'date', 'modified', 'date_gmt', 'modified_gmt' ],

			/**
			 * Mixin for all content that is time stamped.
			 *
			 * This mixin converts between mysql timestamps and JavaScript Dates when syncing a model
			 * to or from the server. For example, a date stored as `2015-12-27T21:22:24` on the server
			 * gets expanded to `Sun Dec 27 2015 14:22:24 GMT-0700 (MST)` when the model is fetched.
			 *
			 * @type {{toJSON: toJSON, parse: parse}}.
			 */
			TimeStampedMixin = {
				/**
				 * Serialize the entity pre-sync.
				 *
				 * @returns {*}.
				 */
				toJSON: function() {
					var attributes = _.clone( this.attributes );

					// Serialize Date objects back into 8601 strings.
					_.each( parseableDates, function( key ) {
						if ( key in attributes ) {

							// Don't convert null values
							if ( ! _.isNull( attributes[ key ] ) ) {
								attributes[ key ] = attributes[ key ].toISOString();
							}
						}
					} );

					return attributes;
				},

				/**
				 * Unserialize the fetched response.
				 *
				 * @param {*} response.
				 * @returns {*}.
				 */
				parse: function( response ) {
					var timestamp;

					// Parse dates into native Date objects.
					_.each( parseableDates, function( key ) {
						if ( ! ( key in response ) ) {
							return;
						}

						// Don't convert null values
						if ( ! _.isNull( response[ key ] ) ) {
							timestamp = wp.api.utils.parseISO8601( response[ key ] );
							response[ key ] = new Date( timestamp );
						}
					});

					return response;
				}
			},

			/**
			 * Build a helper function to retrieve related model.
			 *
			 * @param  {string} parentModel      The parent model.
			 * @param  {int}    modelId          The model ID if the object to request
			 * @param  {string} modelName        The model name to use when constructing the model.
			 * @param  {string} embedSourcePoint Where to check the embedds object for _embed data.
			 * @param  {string} embedCheckField  Which model field to check to see if the model has data.
			 *
			 * @return {Deferred.promise}        A promise which resolves to the constructed model.
			 */
			buildModelGetter = function( parentModel, modelId, modelName, embedSourcePoint, embedCheckField ) {
				var getModel, embeddeds, attributes, deferred;

				deferred  = jQuery.Deferred();
				embeddeds = parentModel.get( '_embedded' ) || {};

				// Verify that we have a valied author id.
				if ( ! _.isNumber( modelId ) ) {
					deferred.reject();
					return deferred;
				}

				// If we have embedded object data, use that when constructing the getModel.
				if ( embeddeds[ embedSourcePoint ] ) {
					attributes = _.findWhere( embeddeds[ embedSourcePoint ], { id: modelId } );
				}

				// Otherwise use the modelId.
				if ( ! attributes ) {
					attributes = { id: modelId };
				}

				// Create the new getModel model.
				getModel = new wp.api.models[ modelName ]( attributes );

				// If we didn’t have an embedded getModel, fetch the getModel data.
				if ( ! getModel.get( embedCheckField ) ) {
					getModel.fetch( { success: function( getModel ) {
						deferred.resolve( getModel );
					} } );
				} else {
					deferred.resolve( getModel );
				}

				// Return a promise.
				return deferred.promise();
			},

			/**
			 * Build a helper to retrieve a collection.
			 *
			 * @param  {string} parentModel      The parent model.
			 * @param  {string} collectionName   The name to use when constructing the collection.
			 * @param  {string} embedSourcePoint Where to check the embedds object for _embed data.
			 * @param  {string} embedIndex       An addiitonal optional index for the _embed data.
			 *
			 * @return {Deferred.promise}        A promise which resolves to the constructed collection.
			 */
			buildCollectionGetter = function( parentModel, collectionName, embedSourcePoint, embedIndex ) {
				/**
				 * Returns a promise that resolves to the requested collection
				 *
				 * Uses the embedded data if available, otherwises fetches the
				 * data from the server.
				 *
				 * @return {Deferred.promise} promise Resolves to a wp.api.collections[ collectionName ]
				 * collection.
				 */
				var postId, embeddeds, getObjects,
					classProperties = '',
					properties      = '',
					deferred        = jQuery.Deferred();

				postId    = parentModel.get( 'id' );
				embeddeds = parentModel.get( '_embedded' ) || {};

				// Verify that we have a valied post id.
				if ( ! _.isNumber( postId ) || 0 === postId ) {
					deferred.reject();
					return deferred;
				}

				// If we have embedded getObjects data, use that when constructing the getObjects.
				if ( ! _.isUndefined( embedSourcePoint ) && ! _.isUndefined( embeddeds[ embedSourcePoint ] ) ) {

					// Some embeds also include an index offset, check for that.
					if ( _.isUndefined( embedIndex ) ) {

						// Use the embed source point directly.
						properties = embeddeds[ embedSourcePoint ];
					} else {

						// Add the index to the embed source point.
						properties = embeddeds[ embedSourcePoint ][ embedIndex ];
					}
				} else {

					// Otherwise use the postId.
					classProperties = { parent: postId };
				}

				// Create the new getObjects collection.
				getObjects = new wp.api.collections[ collectionName ]( properties, classProperties );

				// If we didn’t have embedded getObjects, fetch the getObjects data.
				if ( _.isUndefined( getObjects.models[0] ) ) {
					getObjects.fetch( { success: function( getObjects ) {

						// Add a helper 'parent_post' attribute onto the model.
						setHelperParentPost( getObjects, postId );
						deferred.resolve( getObjects );
					} } );
				} else {

					// Add a helper 'parent_post' attribute onto the model.
					setHelperParentPost( getObjects, postId );
					deferred.resolve( getObjects );
				}

				// Return a promise.
				return deferred.promise();

			},

			/**
			 * Set the model post parent.
			 */
			setHelperParentPost = function( collection, postId ) {

				// Attach post_parent id to the collection.
				_.each( collection.models, function( model ) {
					model.set( 'parent_post', postId );
				} );
			},

			/**
			 * Add a helper funtion to handle post Meta.
			 */
			MetaMixin = {
				getMeta: function() {
					return buildCollectionGetter( this, 'PostMeta', 'https://api.w.org/meta' );
				}
			},

			/**
			 * Add a helper funtion to handle post Revisions.
			 */
			RevisionsMixin = {
				getRevisions: function() {
					return buildCollectionGetter( this, 'PostRevisions' );
				}
			},

			/**
			 * Add a helper funtion to handle post Tags.
			 */
			TagsMixin = {

				/**
				 * Get the tags for a post.
				 *
				 * @return {Deferred.promise} promise Resolves to an array of tags.
				 */
				getTags: function() {
					var tagIds = this.get( 'tags' ),
						tags  = new wp.api.collections.Tags();

					// Resolve with an empty array if no tags.
					if ( _.isEmpty( tagIds ) ) {
						return jQuery.Deferred().resolve( [] );
					}

					return tags.fetch( { data: { include: tagIds } } );
				},

				/**
				 * Set the tags for a post.
				 *
				 * Accepts an array of tag slugs, or a Tags collection.
				 *
				 * @param {array|Backbone.Collection} tags The tags to set on the post.
				 *
				 */
				setTags: function( tags ) {
					var allTags, newTag,
						self = this,
						newTags = [];

					if ( _.isString( tags ) ) {
						return false;
					}

					// If this is an array of slugs, build a collection.
					if ( _.isArray( tags ) ) {

						// Get all the tags.
						allTags = new wp.api.collections.Tags();
						allTags.fetch( {
							data:    { per_page: 100 },
							success: function( alltags ) {

								// Find the passed tags and set them up.
								_.each( tags, function( tag ) {
									newTag = new wp.api.models.Tag( alltags.findWhere( { slug: tag } ) );

									// Tie the new tag to the post.
									newTag.set( 'parent_post', self.get( 'id' ) );

									// Add the new tag to the collection.
									newTags.push( newTag );
								} );
								tags = new wp.api.collections.Tags( newTags );
								self.setTagsWithCollection( tags );
							}
						} );

					} else {
						this.setTagsWithCollection( tags );
					}
				},

				/**
				 * Set the tags for a post.
				 *
				 * Accepts a Tags collection.
				 *
				 * @param {array|Backbone.Collection} tags The tags to set on the post.
				 *
				 */
				setTagsWithCollection: function( tags ) {

					// Pluck out the category ids.
					this.set( 'tags', tags.pluck( 'id' ) );
					return this.save();
				}
			},

			/**
			 * Add a helper funtion to handle post Categories.
			 */
			CategoriesMixin = {

				/**
				 * Get a the categories for a post.
				 *
				 * @return {Deferred.promise} promise Resolves to an array of categories.
				 */
				getCategories: function() {
					var categoryIds = this.get( 'categories' ),
						categories  = new wp.api.collections.Categories();

					// Resolve with an empty array if no categories.
					if ( _.isEmpty( categoryIds ) ) {
						return jQuery.Deferred().resolve( [] );
					}

					return categories.fetch( { data: { include: categoryIds } } );
				},

				/**
				 * Set the categories for a post.
				 *
				 * Accepts an array of category slugs, or a Categories collection.
				 *
				 * @param {array|Backbone.Collection} categories The categories to set on the post.
				 *
				 */
				setCategories: function( categories ) {
					var allCategories, newCategory,
						self = this,
						newCategories = [];

					if ( _.isString( categories ) ) {
						return false;
					}

					// If this is an array of slugs, build a collection.
					if ( _.isArray( categories ) ) {

						// Get all the categories.
						allCategories = new wp.api.collections.Categories();
						allCategories.fetch( {
							data:    { per_page: 100 },
							success: function( allcats ) {

								// Find the passed categories and set them up.
								_.each( categories, function( category ) {
									newCategory = new wp.api.models.Category( allcats.findWhere( { slug: category } ) );

									// Tie the new category to the post.
									newCategory.set( 'parent_post', self.get( 'id' ) );

									// Add the new category to the collection.
									newCategories.push( newCategory );
								} );
								categories = new wp.api.collections.Categories( newCategories );
								self.setCategoriesWithCollection( categories );
							}
						} );

					} else {
						this.setCategoriesWithCollection( categories );
					}

				},

				/**
				 * Set the categories for a post.
				 *
				 * Accepts Categories collection.
				 *
				 * @param {array|Backbone.Collection} categories The categories to set on the post.
				 *
				 */
				setCategoriesWithCollection: function( categories ) {

					// Pluck out the category ids.
					this.set( 'categories', categories.pluck( 'id' ) );
					return this.save();
				}
			},

			/**
			 * Add a helper function to retrieve the author user model.
			 */
			AuthorMixin = {
				getAuthorUser: function() {
					return buildModelGetter( this, this.get( 'author' ), 'User', 'author', 'name' );
				}
			},

			/**
			 * Add a helper function to retrieve the featured image.
			 */
			FeaturedImageMixin = {
				getFeaturedImage: function() {
					return buildModelGetter( this, this.get( 'featured_image' ), 'Media', 'https://api.w.org/featuredmedia', 'source_url' );
				}
			};

		// Exit if we don't have valid model defaults.
		if ( _.isUndefined( model.prototype.args ) ) {
			return model;
		}

		// Go thru the parsable date fields, if our model contains any of them it gets the TimeStampedMixin.
		_.each( parseableDates, function( theDateKey ) {
			if ( ! _.isUndefined( model.prototype.args[ theDateKey ] ) ) {
				hasDate = true;
			}
		} );

		// Add the TimeStampedMixin for models that contain a date field.
		if ( hasDate ) {
			model = model.extend( TimeStampedMixin );
		}

		// Add the AuthorMixin for models that contain an author.
		if ( ! _.isUndefined( model.prototype.args.author ) ) {
			model = model.extend( AuthorMixin );
		}

		// Add the FeaturedImageMixin for models that contain a featured_image.
		if ( ! _.isUndefined( model.prototype.args.featured_image ) ) {
			model = model.extend( FeaturedImageMixin );
		}

		// Add the CategoriesMixin for models that support categories collections.
		if ( ! _.isUndefined( model.prototype.args.categories ) ) {
			model = model.extend( CategoriesMixin );
		}

		// Add the MetaMixin for models that support meta collections.
		if ( ! _.isUndefined( loadingObjects.collections[ modelClassName + 'Meta' ] ) ) {
			model = model.extend( MetaMixin );
		}

		// Add the TagsMixin for models that support tags collections.
		if ( ! _.isUndefined( model.prototype.args.tags ) ) {
			model = model.extend( TagsMixin );
		}

		// Add the RevisionsMixin for models that support revisions collections.
		if ( ! _.isUndefined( loadingObjects.collections[ modelClassName + 'Revisions' ] ) ) {
			model = model.extend( RevisionsMixin );
		}

		return model;
	};

})( window );

/* global wpApiSettings:false */

// Suppress warning about parse function's unused "options" argument:
/* jshint unused:false */
(function() {

	'use strict';

	var wpApiSettings = window.wpApiSettings || {};

	/**
	 * Backbone base model for all models.
	 */
	wp.api.WPApiBaseModel = Backbone.Model.extend(
		/** @lends WPApiBaseModel.prototype  */
		{
			/**
			 * Set nonce header before every Backbone sync.
			 *
			 * @param {string} method.
			 * @param {Backbone.Model} model.
			 * @param {{beforeSend}, *} options.
			 * @returns {*}.
			 */
			sync: function( method, model, options ) {
				var beforeSend;

				options = options || {};

				// Remove date_gmt if null.
				if ( _.isNull( model.get( 'date_gmt' ) ) ) {
					model.unset( 'date_gmt' );
				}

				// Remove slug if empty.
				if ( _.isEmpty( model.get( 'slug' ) ) ) {
					model.unset( 'slug' );
				}

				if ( ! _.isUndefined( wpApiSettings.nonce ) && ! _.isNull( wpApiSettings.nonce ) ) {
					beforeSend = options.beforeSend;

					// @todo enable option for jsonp endpoints
					// options.dataType = 'jsonp';

					options.beforeSend = function( xhr ) {
						xhr.setRequestHeader( 'X-WP-Nonce', wpApiSettings.nonce );

						if ( beforeSend ) {
							return beforeSend.apply( this, arguments );
						}
					};
				}

				// Add '?force=true' to use delete method when required.
				if ( this.requireForceForDelete && 'delete' === method ) {
					model.url = model.url() + '?force=true';
				}
				return Backbone.sync( method, model, options );
			},

			/**
			 * Save is only allowed when the PUT OR POST methods are available for the endpoint.
			 */
			save: function( attrs, options ) {

				// Do we have the put method, then execute the save.
				if ( _.includes( this.methods, 'PUT' ) || _.includes( this.methods, 'POST' ) ) {

					// Proxy the call to the original save function.
					return Backbone.Model.prototype.save.call( this, attrs, options );
				} else {

					// Otherwise bail, disallowing action.
					return false;
				}
			},

			/**
			 * Delete is only allowed when the DELETE method is available for the endpoint.
			 */
			destroy: function( options ) {

				// Do we have the DELETE method, then execute the destroy.
				if ( _.includes( this.methods, 'DELETE' ) ) {

					// Proxy the call to the original save function.
					return Backbone.Model.prototype.destroy.call( this, options );
				} else {

					// Otherwise bail, disallowing action.
					return false;
				}
			}

		}
	);

	/**
	 * API Schema model. Contains meta information about the API.
	 */
	wp.api.models.Schema = wp.api.WPApiBaseModel.extend(
		/** @lends Schema.prototype  */
		{
			defaults: {
				_links: {},
				namespace: null,
				routes: {}
			},

			initialize: function( attributes, options ) {
				var model = this;
				options = options || {};

				wp.api.WPApiBaseModel.prototype.initialize.call( model, attributes, options );

				model.apiRoot = options.apiRoot || wpApiSettings.root;
				model.versionString = options.versionString || wpApiSettings.versionString;
			},

			url: function() {
				return this.apiRoot + this.versionString;
			}
		}
	);
})();

( function() {

	'use strict';

	var wpApiSettings = window.wpApiSettings || {};

	/**
	 * Contains basic collection functionality such as pagination.
	 */
	wp.api.WPApiBaseCollection = Backbone.Collection.extend(
		/** @lends BaseCollection.prototype  */
		{

			/**
			 * Setup default state.
			 */
			initialize: function( models, options ) {
				this.state = {
					data: {},
					currentPage: null,
					totalPages: null,
					totalObjects: null
				};
				if ( _.isUndefined( options ) ) {
					this.parent = '';
				} else {
					this.parent = options.parent;
				}
			},

			/**
			 * Overwrite Backbone.Collection.sync to pagination state based on response headers.
			 *
			 * Set nonce header before every Backbone sync.
			 *
			 * @param {string} method.
			 * @param {Backbone.Model} model.
			 * @param {{success}, *} options.
			 * @returns {*}.
			 */
			sync: function( method, model, options ) {
				var beforeSend, success,
					self = this;

				options    = options || {};
				beforeSend = options.beforeSend;

				if ( 'undefined' !== typeof wpApiSettings.nonce ) {
					options.beforeSend = function( xhr ) {
						xhr.setRequestHeader( 'X-WP-Nonce', wpApiSettings.nonce );

						if ( beforeSend ) {
							return beforeSend.apply( self, arguments );
						}
					};
				}

				if ( 'read' === method ) {
					if ( options.data ) {
						self.state.data = _.clone( options.data );

						delete self.state.data.page;
					} else {
						self.state.data = options.data = {};
					}

					if ( 'undefined' === typeof options.data.page ) {
						self.state.currentPage = null;
						self.state.totalPages = null;
						self.state.totalObjects = null;
					} else {
						self.state.currentPage = options.data.page - 1;
					}

					success = options.success;
					options.success = function( data, textStatus, request ) {
						if ( ! _.isUndefined( request ) ) {
							self.state.totalPages = parseInt( request.getResponseHeader( 'x-wp-totalpages' ), 10 );
							self.state.totalObjects = parseInt( request.getResponseHeader( 'x-wp-total' ), 10 );
						}

						if ( null === self.state.currentPage ) {
							self.state.currentPage = 1;
						} else {
							self.state.currentPage++;
						}

						if ( success ) {
							return success.apply( this, arguments );
						}
					};
				}

				return Backbone.sync( method, model, options );
			},

			/**
			 * Fetches the next page of objects if a new page exists.
			 *
			 * @param {data: {page}} options.
			 * @returns {*}.
			 */
			more: function( options ) {
				options = options || {};
				options.data = options.data || {};

				_.extend( options.data, this.state.data );

				if ( 'undefined' === typeof options.data.page ) {
					if ( ! this.hasMore() ) {
						return false;
					}

					if ( null === this.state.currentPage || this.state.currentPage <= 1 ) {
						options.data.page = 2;
					} else {
						options.data.page = this.state.currentPage + 1;
					}
				}

				return this.fetch( options );
			},

			/**
			 * Returns true if there are more pages of objects available.
			 *
			 * @returns null|boolean.
			 */
			hasMore: function() {
				if ( null === this.state.totalPages ||
					 null === this.state.totalObjects ||
					 null === this.state.currentPage ) {
					return null;
				} else {
					return ( this.state.currentPage < this.state.totalPages );
				}
			}
		}
	);

} )();

( function() {

	'use strict';

	var Endpoint, initializedDeferreds = {},
		wpApiSettings = window.wpApiSettings || {};
	window.wp = window.wp || {};
	wp.api    = wp.api || {};

	if ( _.isEmpty( wpApiSettings ) ) {
		wpApiSettings.root = window.location.origin + '/wp-json/';
	}

	Endpoint = Backbone.Model.extend({
		defaults: {
			apiRoot: wpApiSettings.root,
			versionString: wp.api.versionString,
			schema: null,
			models: {},
			collections: {}
		},

		initialize: function() {
			var model = this, deferred;

			Backbone.Model.prototype.initialize.apply( model, arguments );

			deferred = jQuery.Deferred();
			model.schemaConstructed = deferred.promise();

			model.schemaModel = new wp.api.models.Schema( null, {
				apiRoot: model.get( 'apiRoot' ),
				versionString: model.get( 'versionString' )
			});

			model.schemaModel.once( 'change', function() {
				model.constructFromSchema();
				deferred.resolve( model );
			} );

			if ( model.get( 'schema' ) ) {

				// Use schema supplied as model attribute.
				model.schemaModel.set( model.schemaModel.parse( model.get( 'schema' ) ) );
			} else if ( ! _.isUndefined( sessionStorage ) && sessionStorage.getItem( 'wp-api-schema-model' + model.get( 'apiRoot' ) + model.get( 'versionString' ) ) ) {

				// Used a cached copy of the schema model if available.
				model.schemaModel.set( model.schemaModel.parse( JSON.parse( sessionStorage.getItem( 'wp-api-schema-model' + model.get( 'apiRoot' ) + model.get( 'versionString' ) ) ) ) );
			} else {
				model.schemaModel.fetch({
					/**
					 * When the server return the schema model data, store the data in a sessionCache so we don't
					 * have to retrieve it again for this session. Then, construct the models and collections based
					 * on the schema model data.
					 */
					success: function( newSchemaModel ) {

						// Store a copy of the schema model in the session cache if available.
						if ( ! _.isUndefined( sessionStorage ) ) {
							sessionStorage.setItem( 'wp-api-schema-model' + model.get( 'apiRoot' ) + model.get( 'versionString' ), JSON.stringify( newSchemaModel ) );
						}
					},

					// @todo Handle the error condition.
					error: function() {
					}
				});
			}
		},

		constructFromSchema: function() {
			var routeModel = this, modelRoutes, collectionRoutes, schemaRoot, loadingObjects,

			/**
			 * Set up the model and collection name mapping options. As the schema is built, the
			 * model and collection names will be adjusted if they are found in the mapping object.
			 *
			 * Localizing a variable wpApiSettings.mapping will over-ride the default mapping options.
			 *
			 */
			mapping = wpApiSettings.mapping || {
				models: {
					'Categories':      'Category',
					'Comments':        'Comment',
					'Pages':           'Page',
					'PagesMeta':       'PageMeta',
					'PagesRevisions':  'PageRevision',
					'Posts':           'Post',
					'PostsCategories': 'PostCategory',
					'PostsRevisions':  'PostRevision',
					'PostsTags':       'PostTag',
					'Schema':          'Schema',
					'Statuses':        'Status',
					'Tags':            'Tag',
					'Taxonomies':      'Taxonomy',
					'Types':           'Type',
					'Users':           'User'
				},
				collections: {
					'PagesMeta':       'PageMeta',
					'PagesRevisions':  'PageRevisions',
					'PostsCategories': 'PostCategories',
					'PostsMeta':       'PostMeta',
					'PostsRevisions':  'PostRevisions',
					'PostsTags':       'PostTags'
				}
			};

			/**
			 * Iterate thru the routes, picking up models and collections to build. Builds two arrays,
			 * one for models and one for collections.
			 */
			modelRoutes                = [];
			collectionRoutes           = [];
			schemaRoot                 = routeModel.get( 'apiRoot' ).replace( wp.api.utils.getRootUrl(), '' );
			loadingObjects             = {};

			/**
			 * Tracking objects for models and collections.
			 */
			loadingObjects.models      = routeModel.get( 'models' );
			loadingObjects.collections = routeModel.get( 'collections' );

			_.each( routeModel.schemaModel.get( 'routes' ), function( route, index ) {

				// Skip the schema root if included in the schema.
				if ( index !== routeModel.get( ' versionString' ) &&
						index !== schemaRoot &&
						index !== ( '/' + routeModel.get( 'versionString' ).slice( 0, -1 ) )
				) {

					// Single items end with a regex (or the special case 'me').
					if ( /.*[+)|me]$/.test( index ) ) {
						modelRoutes.push( { index: index, route: route } );
					} else {

						// Collections end in a name.
						collectionRoutes.push( { index: index, route: route } );
					}
				}
			} );

			/**
			 * Construct the models.
			 *
			 * Base the class name on the route endpoint.
			 */
			_.each( modelRoutes, function( modelRoute ) {

				// Extract the name and any parent from the route.
				var modelClassName,
						routeName  = wp.api.utils.extractRoutePart( modelRoute.index, 2 ),
						parentName = wp.api.utils.extractRoutePart( modelRoute.index, 4 ),
						routeEnd   = wp.api.utils.extractRoutePart( modelRoute.index, 1 );

				// Handle the special case of the 'me' route.
				if ( 'me' === routeEnd ) {
					routeName = 'me';
				}

				// If the model has a parent in its route, add that to its class name.
				if ( '' !== parentName && parentName !== routeName ) {
					modelClassName = wp.api.utils.capitalize( parentName ) + wp.api.utils.capitalize( routeName );
					modelClassName = mapping.models[ modelClassName ] || modelClassName;
					loadingObjects.models[ modelClassName ] = wp.api.WPApiBaseModel.extend( {

						// Function that returns a constructed url based on the parent and id.
						url: function() {
							var url = routeModel.get( 'apiRoot' ) + routeModel.get( 'versionString' ) +
									parentName +  '/' +
									( ( _.isUndefined( this.get( 'parent' ) ) || 0 === this.get( 'parent' ) ) ?
										this.get( 'parent_post' ) :
										this.get( 'parent' ) ) + '/' +
									routeName;
							if ( ! _.isUndefined( this.get( 'id' ) ) ) {
								url +=  '/' + this.get( 'id' );
							}
							return url;
						},

						// Include a reference to the original route object.
						route: modelRoute,

						// Include a reference to the original class name.
						name: modelClassName,

						// Include the array of route methods for easy reference.
						methods: modelRoute.route.methods,

						initialize: function() {
							/**
							 * Posts and pages support trashing, other types don't support a trash
							 * and require that you pass ?force=true to actually delete them.
							 *
							 * @todo we should be getting trashability from the Schema, not hard coding types here.
							 */
							if (
								'Posts' !== this.name &&
								'Pages' !== this.name &&
								_.includes( this.methods, 'DELETE' )
							) {
								this.requireForceForDelete = true;
							}
						}
					} );
				} else {

					// This is a model without a parent in its route
					modelClassName = wp.api.utils.capitalize( routeName );
					modelClassName = mapping.models[ modelClassName ] || modelClassName;
					loadingObjects.models[ modelClassName ] = wp.api.WPApiBaseModel.extend( {

						// Function that returns a constructed url based on the id.
						url: function() {
							var url = routeModel.get( 'apiRoot' ) +
								routeModel.get( 'versionString' ) +
								( ( 'me' === routeName ) ? 'users/me' : routeName );

							if ( ! _.isUndefined( this.get( 'id' ) ) ) {
								url +=  '/' + this.get( 'id' );
							}
							return url;
						},

						// Include a reference to the original route object.
						route: modelRoute,

						// Include a reference to the original class name.
						name: modelClassName,

						// Include the array of route methods for easy reference.
						methods: modelRoute.route.methods
					} );
				}

				// Add defaults to the new model, pulled form the endpoint
				wp.api.utils.decorateFromRoute( modelRoute.route.endpoints, loadingObjects.models[ modelClassName ] );

			} );

			/**
			 * Construct the collections.
			 *
			 * Base the class name on the route endpoint.
			 */
			_.each( collectionRoutes, function( collectionRoute ) {

				// Extract the name and any parent from the route.
				var collectionClassName, modelClassName,
						routeName  = collectionRoute.index.slice( collectionRoute.index.lastIndexOf( '/' ) + 1 ),
						parentName = wp.api.utils.extractRoutePart( collectionRoute.index, 3 );

				// If the collection has a parent in its route, add that to its class name/
				if ( '' !== parentName && parentName !== routeName ) {

					collectionClassName = wp.api.utils.capitalize( parentName ) + wp.api.utils.capitalize( routeName );
					modelClassName      = mapping.models[ collectionClassName ] || collectionClassName;
					collectionClassName = mapping.collections[ collectionClassName ] || collectionClassName;
					loadingObjects.collections[ collectionClassName ] = wp.api.WPApiBaseCollection.extend( {

						// Function that returns a constructed url passed on the parent.
						url: function() {
							return routeModel.get( 'apiRoot' ) + routeModel.get( 'versionString' ) +
									parentName + '/' + this.parent + '/' +
									routeName;
						},

						// Specify the model that this collection contains.
						model: loadingObjects.models[ modelClassName ],

						// Include a reference to the original class name.
						name: collectionClassName,

						// Include a reference to the original route object.
						route: collectionRoute,

						// Include the array of route methods for easy reference.
						methods: collectionRoute.route.methods
					} );
				} else {

					// This is a collection without a parent in its route.
					collectionClassName = wp.api.utils.capitalize( routeName );
					modelClassName      = mapping.models[ collectionClassName ] || collectionClassName;
					collectionClassName = mapping.collections[ collectionClassName ] || collectionClassName;
					loadingObjects.collections[ collectionClassName ] = wp.api.WPApiBaseCollection.extend( {

						// For the url of a root level collection, use a string.
						url: routeModel.get( 'apiRoot' ) + routeModel.get( 'versionString' ) + routeName,

						// Specify the model that this collection contains.
						model: loadingObjects.models[ modelClassName ],

						// Include a reference to the original class name.
						name: collectionClassName,

						// Include a reference to the original route object.
						route: collectionRoute,

						// Include the array of route methods for easy reference.
						methods: collectionRoute.route.methods
					} );
				}

				// Add defaults to the new model, pulled form the endpoint
				wp.api.utils.decorateFromRoute( collectionRoute.route.endpoints, loadingObjects.collections[ collectionClassName ] );
			} );

			// Add mixins and helpers for each of the models.
			_.each( loadingObjects.models, function( model, index ) {
				loadingObjects.models[ index ] = wp.api.utils.addMixinsAndHelpers( model, index, loadingObjects );
			} );

		}

	});

	wp.api.endpoints = new Backbone.Collection({
		model: Endpoint
	});

	/**
	 * Initialize the wp-api, optionally passing the API root.
	 *
	 * @param {object} [args]
	 * @param {string} [args.apiRoot] The api root. Optional, defaults to wpApiSettings.root.
	 * @param {string} [args.versionString] The version string. Optional, defaults to wpApiSettings.root.
	 * @param {object} [args.schema] The schema. Optional, will be fetched from API if not provided.
	 */
	wp.api.init = function( args ) {
		var endpoint, attributes = {}, deferred, promise;

		args = args || {};
		attributes.apiRoot = args.apiRoot || wpApiSettings.root;
		attributes.versionString = args.versionString || wpApiSettings.versionString;
		attributes.schema = args.schema || null;
		if ( ! attributes.schema && attributes.apiRoot === wpApiSettings.root && attributes.versionString === wpApiSettings.versionString ) {
			attributes.schema = wpApiSettings.schema;
		}

		if ( ! initializedDeferreds[ attributes.apiRoot + attributes.versionString ] ) {
			endpoint = wp.api.endpoints.findWhere( { apiRoot: attributes.apiRoot, versionString: attributes.versionString } );
			if ( ! endpoint ) {
				endpoint = new Endpoint( attributes );
				wp.api.endpoints.add( endpoint );
			}
			deferred = jQuery.Deferred();
			promise = deferred.promise();

			endpoint.schemaConstructed.done( function( endpoint ) {

				// Map the default endpoints, extending any already present items (including Schema model).
				wp.api.models      = _.extend( endpoint.get( 'models' ), wp.api.models );
				wp.api.collections = _.extend( endpoint.get( 'collections' ), wp.api.collections );
				deferred.resolveWith( wp.api, [ endpoint ] );
			} );
			initializedDeferreds[ attributes.apiRoot + attributes.versionString ] = promise;
		}
		return initializedDeferreds[ attributes.apiRoot + attributes.versionString ];
	};

	/**
	 * Construct the default endpoints and add to an endpoints collection.
	 */

	// The wp.api.init function returns a promise that will resolve with the endpoint once it is ready.
	wp.api.loadPromise = wp.api.init();

} )();