jQuery 3.0 的 Data 浅析

jQuery.expando = "jQuery" + ( version + Math.random() ).replace( /\D/g, "" )

"jQuery" + "3.0.0" + 0.129896303388626 == "jQuery3.0.00.129896303388626"

"jQuery30009423638425146147"

jQuery 300 024727210109188635 1
jQuery 300 024727210109188635 2

var acceptData = function( owner ) {

	// Accepts only:
	//  - Node
	//    - Node.ELEMENT_NODE
	//    - Node.DOCUMENT_NODE
	//  - Object
	//    - Any
	/* jshint -W018 */
	return owner.nodeType === 1 || owner.nodeType === 9 || !( +owner.nodeType );
};

// If it is a node unlikely to be stringify-ed or looped over
// use plain assignment
if ( owner.nodeType ) {
	owner[ this.expando ] = value;

// Otherwise secure it in a non-enumerable property
// configurable must be true to allow the property to be
// deleted when data is removed
} else {
	Object.defineProperty( owner, this.expando, {
		value: value,
		configurable: true
	} );
}

elem['jQuery3000247272101091886351'] = dataObj;

var person = {name: 'John', age: 30};
Object.defineProperty( person, 'jQuery3000247272101091886351', {
	value: dataObj,
	configurable: true
} );

cache: function( owner ) {

	// Check if the owner object already has a cache
	var value = owner[ this.expando ];

	// If not, create one
	if ( !value ) {
		value = {};

		// We can accept data for non-element nodes in modern browsers,
		// but we should not, see #8335.
		// Always return an empty object.
		if ( acceptData( owner ) ) {

			// If it is a node unlikely to be stringify-ed or looped over
			// use plain assignment
			if ( owner.nodeType ) {
				owner[ this.expando ] = value;

			// Otherwise secure it in a non-enumerable property
			// configurable must be true to allow the property to be
			// deleted when data is removed
			} else {
				Object.defineProperty( owner, this.expando, {
					value: value,
					configurable: true
				} );
			}
		}
	}

	return value;
},

set: function( owner, data, value ) {
	var prop,
		cache = this.cache( owner );

	// Handle: [ owner, key, value ] args
	// Always use camelCase key (gh-2257)
	if ( typeof data === "string" ) {
		cache[ jQuery.camelCase( data ) ] = value;

	// Handle: [ owner, { properties } ] args
	} else {

		// Copy the properties one-by-one to the cache object
		for ( prop in data ) {
			cache[ jQuery.camelCase( prop ) ] = data[ prop ];
		}
	}
	return cache;
},

get: function( owner, key ) {
	return key === undefined ?
		this.cache( owner ) :

		// Always use camelCase key (gh-2257)
		owner[ this.expando ] && owner[ this.expando ][ jQuery.camelCase( key ) ];
},

access: function( owner, key, value ) {

	// In cases where either:
	//
	//   1. No key was specified
	//   2. A string key was specified, but no value provided
	//
	// Take the "read" path and allow the get method to determine
	// which value to return, respectively either:
	//
	//   1. The entire cache object
	//   2. The data stored at the key
	//
	if ( key === undefined ||
			( ( key && typeof key === "string" ) && value === undefined ) ) {

		return this.get( owner, key );
	}

	// When the key is not a string, or both a key and value
	// are specified, set or extend (existing objects) with either:
	//
	//   1. An object of properties
	//   2. A key and value
	//
	this.set( owner, key, value );

	// Since the "set" path can have two possible entry points
	// return the expected data based on which path was taken[*]
	return value !== undefined ? value : key;
},

remove: function( owner, key ) {
	var i,
		cache = owner[ this.expando ];

	if ( cache === undefined ) {
		return;
	}

	if ( key !== undefined ) {

		// Support array or space separated string of keys
		if ( jQuery.isArray( key ) ) {

			// If key is an array of keys...
			// We always set camelCase keys, so remove that.
			key = key.map( jQuery.camelCase );
		} else {
			key = jQuery.camelCase( key );

			// If a key with the spaces exists, use it.
			// Otherwise, create an array by matching non-whitespace
			key = key in cache ?
				[ key ] :
				( key.match( rnotwhite ) || [] );
		}

		i = key.length;

		while ( i-- ) {
			delete cache[ key[ i ] ];
		}
	}

	// Remove the expando if there's no more data
	if ( key === undefined || jQuery.isEmptyObject( cache ) ) {

		// Support: Chrome <=35 - 45
		// Webkit & Blink performance suffers when deleting properties
		// from DOM nodes, so set to undefined instead
		// https://bugs.chromium.org/p/chromium/issues/detail?id=378607 (bug restricted)
		if ( owner.nodeType ) {
			owner[ this.expando ] = undefined;
		} else {
			delete owner[ this.expando ];
		}
	}
},　

hasData: function( owner ) {
	var cache = owner[ this.expando ];
	return cache !== undefined && !jQuery.isEmptyObject( cache );
}

dataPriv
	
	公共
		$.hasData
		$.cleanData
		cloneCopyEvent

	队列
		$().queue
		$()._queueHooks
		$().promise

	动画
		$().animate
		$().stop
		$().finish
		showHide

	事件
		$.event.add
		$.event.remove
		$.event.dispatch
		$.event.trigger
	
	其它
		setGlobalEval
		domManip
		defaultPrefilter
		$().toggleClass

dataUser

	公共
		$.hasData
		$.cleanData
		cloneCopyEvent

	数据缓存
		$.data
		$.removeData
		$().data
		$().removeData

	其它
		dataAttr

hasData: function( elem ) {
return dataUser.hasData( elem ) || dataPriv.hasData( elem );
},

var cloneNode = $.clone(elem);