jQuery Data Manipulate API - A source code dissecting journey

jQuery Data Manipulate
A source code dissecting journey
Huiyi Yan

HTML5 data-* Attributes
<li class="user" data-name="John Resig" data-city="Boston"
data-lang="js" data-food="Bacon">
<b>John says:</b> <span>Hello, how are you?</span>
</li>
var user = document.getElementsByTagName("li")[0];
var pos = 0, span = user.getElementsByTagName("span")[0];
var phrases = [
{name: "city", prefix: "I am from "},
{name: "food", prefix: "I like to eat "},
{name: "lang", prefix: "I like to program in "}
];
user.addEventListener( "click", function(){
var phrase = phrases[ pos++ ];
// Use the .dataset property
span.innerHTML = phrase.prefix + user.dataset[ phrase.name ];
}, false);
REF> http://ejohn.org/blog/html-5-data-attributes/

span.innerHTML = phrase.prefix +
user.getAttribute("data-" + phrase.name )
The .dataset property behaves very similarly to
the the .attributes property (but it only works as
a map of key-value pairs)

While I firmly believe that useful data should be made visible to users, there are
circumstances where data-* attributes make sense. For instance, including
data-lat and data-lng attributes in an element containing a street address would
allow for easily adding markers to a Google Map on the page:
<span
data-lat="38.8951"
data-lng="-77.0363">
1600 Pennsylvania Ave.
Washington, DC
</span>
“
”
REF> http://www.viget.com/inspire/extending-paul-irishs-comprehensive-dom-ready-execution/

Taking a step back, we can use data-* attributes on the body element to
provide an indication of where we are within an application:
<body data-controller="<%= controller_name %>" data-
action="<%= action_name %>">
<body data-controller="users" data-action="show">
The above code will yield something like:
REF> http://www.viget.com/inspire/extending-paul-irishs-comprehensive-dom-ready-execution/

.data()/jQuery.data()
.data( key, value )
.data( key, value )
.data( obj )
.data( key )
.data( key )
.data()

<div>
The values stored were
<span></span>
and
<span></span>
</div>
$("div").data("test", { first: 16, last: "pizza!" });
$("span:first").text($("div").data("test").first);
$("span:last").text($("div").data("test").last);
<div data-role="page" data-last-value="43" data-
hidden="true" data-options='{"name":"John"}'></div>
$("div").data("role") === "page";
$("div").data("lastValue") === 43;
$("div").data("hidden") === true;
$("div").data("options").name === "John";

getData – triggered before data is read from the object.
changeData – triggered whenever data is set or changed. It is used
in the jQuery datalink plugin .

. removeData()/ jQuery.removeData()
.removeData( [ name ] )
<div>value1 before creation: <span></span></div>
<div>value1 after creation: <span></span></div>
<div>value1 after removal: <span></span></div>
$("span:eq(0)").text("" + $("div").data("test1"));
$("div").data("test1", "VALUE-1");
$("div").data("test2", "VALUE-2");
$("div").removeData("test1");

jQuery.hasData()
jQuery.hasData( element )
The primary advantage of jQuery.hasData(element) is
that it does not create and associate a data object with
the element if none currently exists. In contrast,
jQuery.data(element) always returns a data object to the
caller, creating one if no data object previously existed.
“
”

jQuery.hasData()
$(function(){
var $p = jQuery("p"), p = $p[0];
$p.append(jQuery.hasData(p)+" "); /* false */
jQuery.data(p, "testing", 123);
$p.append(jQuery.hasData(p)+" "); /* true*/
jQuery.removeData(p, "testing");
$p.append(jQuery.hasData(p)+" "); /* false */
});

Utilities
jQuery.isEmptyObject()
jQuery.trim()
jQuery.isFunction()
jQuery.each()
jQuery.globalEval()
jQuery.merge()
jQuery.proxy()
jQuery.extend()

Utilities
// Populate the class2type map
jQuery.each("Boolean Number String Function Array Date RegExp
Object".split(" "), function(i, name) {
class2type["[object " + name + "]"] =name.toLowerCase();
});
type: function(obj) {
return obj == null ? String(obj) :class2type[toString.cal
l(obj)] || "object";
},
// See test/unit/core.js for details concerning isFunction.
// Since version 1.3, DOM methods and functions like alert
// aren't supported. They return false on IE (#2968).
isFunction: function(obj) {
return jQuery.type(obj) === "function";
},
jQuery.isFunction()

Utilities
// Use native String.trim function wherever possible
trim: trim ?
function(text) {
return text == null ? "" : trim.call(text);
} :
// Otherwise use our own trimming functionality
function(text) {
return text == null ? "" :text.toString().replace(trimLef
t,"")
.replace(trimRight, "");
},
jQuery.trim()

Utilities
isEmptyObject: function(obj) {
for (var name in obj) {
return false;
}
return true;
},
jQuery.isEmptyObject()

Utilities
isPlainObject: function(obj) {
// Must be an Object.
// Because of IE, we also have to check the presence of the constructor
property.
// Make sure that DOM nodes and window objects don't pass through, as well
if (!obj || jQuery.type(obj) !== "object" ||obj.nodeType || jQuery.isWindow(obj
)) {
return false;
}
// Not own constructor property must be Object
if (obj.constructor && !hasOwn.call(obj,"constructor")
&&!hasOwn.call(obj.constructor.prototype,"isPrototypeOf")) {
return false;
}
// Own properties are enumerated firstly, so to speed up,
// if last one is own, then all properties are own.
var key;
for (key in obj) {}
return key === undefined || hasOwn.call(obj,key);
},
jQuery.isPlainObject()

Utilities
globalEval: function(data) {
if (data && rnotwhite.test(data)) {
// We use execScript on Internet Explorer
// We use an anonymous function so that context is
window
// rather than jQuery in Firefox
(window.execScript ||
function(data) {
window["eval"].call(window, data);
})(data);
}
},
jQuery.globalEval()

Utilities
// Bind a function to a context, optionally partially applying any
// arguments.
proxy: function(fn, context) {
if (typeof context === "string") {
var tmp = fn[context];
context = fn;
fn = tmp;
}
// Quick check to determine if target is callable, in the spec
// this throws a TypeError, but we will just return undefined.
if (!jQuery.isFunction(fn)) {
return undefined;
}
// Simulated bind
var args = slice.call(arguments, 2),
proxy = function() {
return fn.apply(context,args.concat(slice.call(arguments)));
};
// Set the guid of unique handler to the same of original handler, so it
can be removed
proxy.guid = fn.guid = fn.guid || proxy.guid ||jQuery.guid++;
return proxy;
},
jQuery.proxy()

UtilitiesjQuery.each()
// args is for internal usage only
each: function(object, callback, args) {
var name, i = 0,
length = object.length,
isObj = length === undefined || jQuery.isFunction(object);
if (args) {
if (isObj) {
for (name in object) {
if (callback.apply(object[name], args) === false) {
break;
}
}
} else {
for (; i < length;) {
if (callback.apply(object[i++], args) === false) {
break;
}
}
}

UtilitiesjQuery.each()
// A special, fast, case for the most common use of each
} else {
if (isObj) {
for (name in object) {
if (callback.call(object[name], name, object[name])
===false) {
break;
}
}
} else {
for (; i < length;) {
if (callback.call(object[i], i, object[i++]) === fa
lse) {
break;
}
}
}
}
return object;
},

Miscellaneous
.index()
.map()
.get()
.toArray()
.slice()

Miscellaneous
.index()
.index( selector )
selector A selector representing a jQuery collection in
which to look for an element.
.index( element )
element The DOM element or first element within the jQuery
object to look for.

Miscellaneous
<span>Click a div!</span>
<div>First div</div>
<div>Second div</div>
<div>Third div</div>
<script>
$("div").click(function () {
// this is the dom element clicked
var index = $("div").index(this);
$("span").text("That was div index #" + index);
});
</script>
.index()
On click, returns the index (based zero) of that div in the
page.

Miscellaneous
<ul>
<li id="foo">foo</li>
<li id="bar">bar</li>
<li id="baz">baz</li>
</ul>
<div></div>
<script>$('div').html('Index: ' + $('#bar').index('li')
);</script>
.index()
Returns the index for the element with ID bar in relation
to all <li> elements.

Miscellaneous
toArray: function() {
return slice.call(this, 0);
}
Reversed - <span></span>
<div>One</div>
<div>Two</div>
<div>Three</div>
<script>
function disp(divs) {
var a = [];
for (var i = 0; i < divs.length; i++) {
a.push(divs[i].innerHTML);
}
$("span").text(a.join(" "));
}
disp($("div").toArray().reverse());
</script>
toArray()

Miscellaneous
.map(
).map( callback(index, domElement) )
callback(index, domElement)A function object that will be
invoked for each element in the current set.

Miscellaneous
<input type="button" value="equalize div heights">
<div style="background:red; height: 40px; "></div>
<div style="background:green; height: 70px;"></div>
<div style="background:blue; height: 50px; "></div>
<script>
$.fn.equalizeHeights = function(){
return this.height( Math.max.apply(this,
$(this).map(function(i,e){ return $(e).height() }).get() ) )
}
$('input').click(function(){
$('div').equalizeHeights();
});
</script>
.map(
)Equalize the heights of the divs.

Miscellaneous
map: function(callback) {
return this.pushStack(jQuery.map(this, function(
elem, i) {
return callback.call(elem, i, elem);
}));
},
.map(
)

Miscellaneous// arg is for internal usage only
map: function(elems, callback, arg) {
var value, key, ret = [],
i = 0,
length = elems.length,
// jquery objects are treated as arrays
isArray = elems instanceof jQuery || length !== undefined &&typeof length === "number" &
& ((length > 0 && elems[0] && elems[length -1]) || length === 0 || jQuery.isArray(elems));
// Go through the array, translating each of the items to their
if (isArray) {
for (; i < length; i++) {
value = callback(elems[i], i, arg);
if (value != null) {
ret[ret.length] = value;
}
}
// Go through every key on the object,
} else {
for (key in elems) {
value = callback(elems[key], key, arg);
if (value != null) {
ret[ret.length] = value;
}
}
}
// Flatten any nested arrays
return ret.concat.apply([], ret);
},
.map(
)

Miscellaneous
// Take an array of elements and push it onto the stack
// (returning the new matched element set)
pushStack: function(elems, name, selector) {
// Build a new jQuery matched element set
var ret = this.constructor();
if (jQuery.isArray(elems)) {
push.apply(ret, elems);
} else {
jQuery.merge(ret, elems);
}
// Add the old object onto the stack (as a reference)
ret.prevObject = this;
ret.context = this.context;
if (name === "find") {
ret.selector = this.selector + (this.selector ? " " : "") +selector;
} else if (name) {
ret.selector = this.selector + "." + name + "(" + selector +")";
}
// Return the newly-formed element set
return ret;
},
.map(
)

Miscellaneous
// Determine the position of an element within
// the matched set of elements
index: function(elem) {
if (!elem || typeof elem === "string") {
return jQuery.inArray(this[0],
// If it receives a string, the selector is used
// If it receives nothing, the siblings are used
elem ? jQuery(elem) : this.parent().children());
}
// Locate the position of the desired element
return jQuery.inArray(
// If it receives a jQuery object, the first element is
used
elem.jquery ? elem[0] : elem, this);
},
.index()

Miscellaneous
// Get the Nth element in the matched element set OR
// Get the whole matched element set as a clean array
get: function(num) {
return num == null ?
// Return a 'clean' array
this.toArray() :
// Return just the object
(num < 0 ? this[this.length + num] : this[num]);
},
.get()

General Attributes
.attr()
.removeAttr()
.prop()
.removeProp()

General Attributes
attr: function(name, value) {
return jQuery.access(this, name, value, true, jQuery.a
ttr);
},
removeAttr: function(name) {
return this.each(function() {
jQuery.removeAttr(this, name);
});
},
.attr() .removeAttr()

General Attributes
prop: function(name, value) {
return jQuery.access(this, name, value, true, jQuery.
prop);
},
removeProp: function(name) {
return this.each(function() {
// try/catch handles cases where IE balks (such
as removing a property on window)
try {
this[name] = undefined;
delete this[name];
} catch (e) {}
});
},
.prop() .removeProp()

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