Dollar symbol

Dollar Symbol 深⼊入淺出
Aaron Huang
1

Dollar Symbol 深⼊入淺出
Aaron Huang
2
只進不出

Aaron Huang
• Sr. F2E @
• F2E Lead @ Faria Systems
• Cloud Service Engineer @ Waveface
• Xing “⾏行” - Evernote DevCup 2013 Top 6

https://jquery.org/history/
• Aug 22, 2005 - John Resig ﬁrst hints
• Jan 14, 2006 - jQuery announced
• Jan, 2006 - First jQuery Plugin
• Aug, 2006 - v1.0 released
• Jul, 2007 - jQuery UI announced
• Aug, 2008 - jQuery Conference
• Jan, 2009 - Sizzle.js
•
歷史

• Aug 22, 2005 - John Resig ﬁrst hints
• Jan 14, 2006 - jQuery announced
• Jan, 2006 - First jQuery Plugin
• Aug, 2006 - v1.0 released
• Jul, 2007 - jQuery UI announced
• Nov, 2011 - jQuery Mobile 1.0
• Jan, 2013 - jQuery 1.9, 2.0-beta, jquery migrate
• April 18, 2013 - jQuery 2.0
• Sep 19, 2013 - jQuery 1.11 and 2.1 Beta 1 Released
歷史

• Nov, 2011 - jQuery Mobile 1.0
• Jan, 2013 - jQuery 1.9, 2.0-beta, jquery migrate
• April 18, 2013 - jQuery 2.0
• Sep 19, 2013 - jQuery 1.11 and 2.1 Beta 1 Released

jquery.migrate
http://code.jquery.com/jquery-migrate-1.0.0.js

File concat RequireJS
Module Dependency

File Concat (before v1.11)
•intro.js
•core.js
•selector.js
•…
•…
•outro.js

File Concat (before v1.11)
•intro.js
•core.js
•selector.js
•…
•…
•outro.js
jQuery.jsConcat

RequireJS (After v1.11)
•core/
•var/
•event/
•…./
•jquery.js
•core.js
•event.js
•selector.js
•…
•…

•core/
•var/
•event/
•…./
•jquery.js
•core.js
•event.js
•selector.js
•…
•…
dependency
resolve
r.js

•core/
•var/
•event/
•…./
•jquery.js
•core.js
•event.js
•selector.js
•…
•…
dependency
resolve
r.js convert
wrap
output

•core/
•var/
•event/
•…./
•jquery.js
•core.js
•event.js
•selector.js
•…
•…
dependency
resolve
r.js convert
wrap
output
jQuery.js

熱⾝身⼀一下
來看看 jQuery.ready 在不同版本下的實作差異

注：$(document).ready 沒事不要⽤用
但是很多⼈人都⽤用過，所以拿來熱⾝身

// $.fn.ready #1
$(document).ready(function(){
// callback content.
});

// $.fn.ready #2
$(function(){
});
// $.fn.ready #1
$(document).ready(function(){
});

// Kick off the DOM ready check even if the user does not
jQuery.ready.promise();
Challenge

// Kick off the DOM ready check even if the user does not
jQuery.ready.promise();
http://macb.in/do3E
Challenge

License
http://blog.jquery.com/2012/09/10/jquery-licensing-changes/

License
MIT/GPL

License
MIT/GPL
MIT

Sign the CLA
(Contributor License Agreement)
http://contribute.jquery.org/CLA/

• vim
• ctags
• sliver_search or ack

讓你的 GitHub ⽤用起來更⽜牛⼀一點

熟記 shortcut
按 “t” 就對了

Octotree
http://sobolev.us/octotree/

Sourcegraph
https://sourcegraph.com/

Github-ﬁnd
http://goo.gl/DR86r1

jQuery.fn.init
a jQuery Object

$('div')
$('#id')
$('.class')
$('<div/>')

$('div')
$('#id')
$('.class')
$('<div/>')
console.log($('#id')); //[<div id="id"></id>]

window.jQuery = window.$ = jQuery;
https://github.com/jquery/jquery/blob/master/src/exports/global.js
src/exports/global.js

// Define a local copy of jQuery
jQuery = function( selector, context ) {
return new jQuery.fn.init( selector, context );
},

// A central reference to the root jQuery(document)
var rootjQuery,
// A simple way to check for HTML strings
// Prioritize #id over <tag> to avoid XSS via location.hash (#9521)
// Strict HTML recognition (#11290: must start with <)
rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/,
init = jQuery.fn.init = function( selector, context ) {
var match, elem;
// HANDLE: $(""), $(null), $(undefined), $(false)
if ( !selector ) {
return this;
}
// Handle HTML strings
if ( typeof selector === "string" ) {
if ( selector[0] === "<" && selector[ selector.length - 1 ] === ">" && selector.length >= 3 ) {
// Assume that strings that start and end with <> are HTML and skip the regex check
match = [ null, selector, null ];
} else {
match = rquickExpr.exec( selector );
}

// A central reference to the root jQuery(document)
var rootjQuery,
// A simple way to check for HTML strings
// Prioritize #id over <tag> to avoid XSS via location.hash (#9521)
// Strict HTML recognition (#11290: must start with <)
rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/,
init = jQuery.fn.init = function( selector, context ) {
var match, elem;
if ( !selector ) {
return this;
}
if ( selector[0] === "<" && selector[ selector.length - 1 ] === ">" && selector.length >= 3 ) {
} else {
}
rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/

Selector 以外的狀況
if ( !selector ) {
return this;
}
// HANDLE: $(function)
// Shortcut for document ready
} else if ( jQuery.isFunction( selector ) ) {
return typeof rootjQuery.ready !== "undefined" ?
rootjQuery.ready( selector ) :
// Execute immediately if ready is not present
selector( jQuery );
}

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
Non-capturing

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
Non-capturing Group 1

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
Non-capturing Group 1 Group 2

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
• match[0] = // Matched String

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
• match[1] = // Tag html

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
• match[2] = // ID name

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
• match[2] = // ID name $('#id')

rquickExpr = /^(?:s*(<[wW]+>)[^>]*|#([w-]*))$/
• match[2] = // ID name $('#id')
$('<div/>')

if ( selector[0] === "<" && selector[ selector.length - 1 ] === ">" && selector.length >= 3 )
} else {
}

// Match html or make sure no context is specified for #id
if ( match && (match[1] || !context) ) {
// HANDLE: $(html) -> $(array)
if ( match[1] ) {
context = context instanceof jQuery ? context[0] : context;
// Option to run scripts is true for back-compat
// Intentionally let the error be thrown if parseHTML is not present
jQuery.merge( this, jQuery.parseHTML(
match[1],
context && context.nodeType ? context.ownerDocument || context : document,
true
) );
// HANDLE: $(html, props)
if ( rsingleTag.test( match[1] ) && jQuery.isPlainObject( context ) ) {
for ( match in context ) {
// Properties of context are called as methods if possible
if ( jQuery.isFunction( this[ match ] ) ) {
this[ match ]( context[ match ] );
// ...and otherwise set as attributes
} else {
this.attr( match, context[ match ] );

// ...and otherwise set as attributes
} else {
this.attr( match, context[ match ] );
}
}
}
return this;
// HANDLE: $(#id)
} else {
elem = document.getElementById( match[2] );
// Support: Blackberry 4.6
// gEBID returns nodes no longer in the document (#6963)
if ( elem && elem.parentNode ) {
// Inject the element directly into the jQuery object
this.length = 1;
this[0] = elem;
}
this.context = document;
this.selector = selector;
return this;
}

this.context = document;
this.selector = selector;
return this;
}
// HANDLE: $(expr, $(...))
} else if ( !context || context.jquery ) {
return ( context || rootjQuery ).find( selector );
// HANDLE: $(expr, context)
// (which is just equivalent to: $(context).find(expr)
} else {
return this.constructor( context ).find( selector );
}

function Sizzle( selector, context, results, seed )

node type
Name Value
ELEMENT_NODE 1
ATTRIBUTE_NODE 2
TEXT_NODE 3
CDATA_SECTION_NODE 4
ENTITY_REFERENCE_NODE 5
ENTITY_NODE 6
PROCESSING_INSTRUCTION_NODE 7
COMMENT_NODE 8
DOCUMENT_NODE 9
DOCUMENT_TYPE_NODE 10
DOCUMENT_FRAGMENT_NODE 11
NOTATION_NODE 12

var match, elem, m, nodeType,
// QSA vars
i, groups, old, nid, newContext, newSelector;
if ( ( context ? context.ownerDocument || context : preferredDoc ) !== document ) {
setDocument( context );
}
context = context || document;
results = results || [];
nodeType = context.nodeType;
if ( typeof selector !== "string" || !selector ||
nodeType !== 1 && nodeType !== 9 && nodeType !== 11 ) {
return results;
}

if ( !seed && documentIsHTML ) {
// Try to shortcut find operations when possible (e.g., not under DocumentFragment)
if ( nodeType !== 11 && (match = rquickExpr.exec( selector )) ) {
// Speed-up: Sizzle("#ID")
if ( (m = match[1]) ) {
if ( nodeType === 9 ) {
elem = context.getElementById( m );
// Check parentNode to catch when Blackberry 4.6 returns
// nodes that are no longer in the document (jQuery #6963)
if ( elem && elem.parentNode ) {
// Handle the case where IE, Opera, and Webkit return items
// by name instead of ID
if ( elem.id === m ) {
results.push( elem );
return results;
}
} else {
return results;
}
} else {
// Context is not a document

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
Group 1

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
Group 1 Group 2

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
Group 1 Group 2 Group 3

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
• match[2] = // TAG name

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
• match[3] = // CLASS name

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
• match[3] = // CLASS name $(‘.class')

rquickExpr = /^(?:#([w-]+)|(w+)|.([w-]+))$/
• match[3] = // CLASS name $(‘.class')
$('div')

} else {
if ( context.ownerDocument && (elem = context.ownerDocument.getElementById( m )) &&
contains( context, elem ) && elem.id === m ) {
return results;
}
}

} else {
if ( context.ownerDocument && (elem = context.ownerDocument.getElementById( m )) &&
contains( context, elem ) && elem.id === m ) {
return results;
}
}
e.g.,$(‘body’).find(‘#id’)

// Speed-up: Sizzle("TAG")
} else if ( match[2] ) {
push.apply( results, context.getElementsByTagName( selector ) );
return results;
// Speed-up: Sizzle(".CLASS")
} else if ( (m = match[3]) && support.getElementsByClassName ) {
push.apply( results, context.getElementsByClassName( m ) );
return results;
}
}

var push = [].push,
slice = [].slice;

Function.prototype.apply()
fun.apply(thisArg[, argsArray])

Function.prototype.apply()
fun.apply(thisArg[, argsArray])
Function.prototype.call()
fun.call(thisArg[, arg1[, arg2[, ...]]])

// QSA path
if ( support.qsa && (!rbuggyQSA || !rbuggyQSA.test( selector )) ) {
nid = old = expando;
newContext = context;
newSelector = nodeType !== 1 && selector;
// qSA works strangely on Element-rooted queries
// We can work around this by specifying an extra ID on the root
// and working up from there (Thanks to Andrew Dupont for the technique)
// IE 8 doesn't work on object elements
if ( nodeType === 1 && context.nodeName.toLowerCase() !== "object" ) {
groups = tokenize( selector );
if ( (old = context.getAttribute("id")) ) {
nid = old.replace( rescape, "$&" );
} else {
context.setAttribute( "id", nid );
}
nid = "[id='" + nid + "'] ";
i = groups.length;
while ( i-- ) {
groups[i] = nid + toSelector( groups[i] );
}
newContext = rsibling.test( selector ) && testContext( context.parentNode ) || context;
newSelector = groups.join(",");
}

Challenge

http://macb.in/1fDSb
Challenge

if ( newSelector ) {
try {
push.apply( results,
newContext.querySelectorAll( newSelector )
);
return results;
} catch(qsaError) {
} finally {
if ( !old ) {
context.removeAttribute("id");
}
}
}
}

Deferred
⾯面試必備的知識

Async JavaScript
好書推薦給你

• Callback
• Event
• Promise

Promise pattern
http://wiki.commonjs.org/wiki/Promises

Promise pattern
http://wiki.commonjs.org/wiki/Promises
許你⼀一個承諾

jQuery.Deferred()
• A constructor function that returns a chainable utility
object with methods to register multiple callbacks into
callback queues, invoke callback queues, and relay the
success or failure state of any synchronous or
asynchronous function.
• jQuery Deferred is based on the CommonJS Promises/A
design.

$.when(OpenDataAt(172800))
.then(resumeWork)
.fail(undefined);
郭董說

.then(resumeWork)
.fail(undefined);
郭董說
48 ⼩小時內公開資料

.then(resumeWork)
.fail(undefined);
郭董說
復⼯工

.then(resumeWork)
.fail(undefined);
郭董說
復⼯工
不然他也不知道該怎麼辦

• .ready
• .ajax
• .animate

了解 Deferred
• ⾏行為
• 假設

了解 Deferred
• ⾏行為
• 假設
• 狀態

了解 Deferred
• ⾏行為
• 假設
• 狀態
(resolve, reject, notify)

了解 Deferred
• ⾏行為
• 假設
• 狀態
(done, fail, progress)

了解 Deferred
• ⾏行為
• 假設
• 狀態
(done, fail, progress)
(resolved, rejected, pending)

• deferred.promise() -> state: pending

• deferred.resolve() -> deferred.done_stack -> state: resolved

• deferred.resolve() -> deferred.done_stack -> state: resolved
• deferred.reject() -> deferred.fail_stack -> state: rejected

Deferred: function( func ) {
var tuples = [
// action, add listener, listener list, final state
[ "resolve", "done", jQuery.Callbacks("once memory"), "resolved" ],
[ "reject", "fail", jQuery.Callbacks("once memory"), "rejected" ],
[ "notify", "progress", jQuery.Callbacks("memory") ]
],
state = "pending",
promise = {
state: function() {
return state;
},
always: function() {
deferred.done( arguments ).fail( arguments );
return this;
},
then: function( /* fnDone, fnFail, fnProgress */ ) {
var fns = arguments;
return jQuery.Deferred(function( newDefer ) {
jQuery.each( tuples, function( i, tuple ) {
var fn = jQuery.isFunction( fns[ i ] ) && fns[ i ];
// deferred[ done | fail | progress ] for forwarding actions to newDefer
deferred[ tuple[1] ](function() {
var returned = fn && fn.apply( this, arguments );

var tuples = [
],

var tuples = [
],
⾏行為

var tuples = [
],
⾏行為假設

var tuples = [
],
⾏行為假設狀態

var tuples = [
],
⾏行為假設狀態Callback list

var tuples = [
],
0
Callback list

var tuples = [
],
0 1
Callback list

var tuples = [
],
0 1 2
Callback list

var tuples = [
],
0 1 2
Callback list
3

想⼀一想
• Deferred 會建構⼀一個全新並獨⽴立的 callbacks list

想⼀一想
• 三個⾏行為定義的 function 幾乎⼀一樣

想⼀一想
• Callbacks list 提供了所有的必要⽅方法, 包含 add, remove, ﬁre, disable

想⼀一想
• Resolve 跟 Reject 是相對的

想⼀一想
• Resolve 跟 Reject 是相對的
• resolve() 與 reject() 其中⼀一⽅方作動, 另⼀一個的 callbacks 則觸發 .disabled()

deferred = {};
// Add list-specific methods
var list = tuple[ 2 ],
stateString = tuple[ 3 ];
// promise[ done | fail | progress ] = list.add
promise[ tuple[1] ] = list.add;
// Handle state
if ( stateString ) {
list.add(function() {
// state = [ resolved | rejected ]
state = stateString;
// [ reject_list | resolve_list ].disable; progress_list.lock
}, tuples[ i ^ 1 ][ 2 ].disable, tuples[ 2 ][ 2 ].lock );
}
// deferred[ resolve | reject | notify ]
deferred[ tuple[0] ] = function() {
deferred[ tuple[0] + "With" ]( this === deferred ? promise : this, arguments );
return this;
};
deferred[ tuple[0] + "With" ] = list.fireWith;

list.add(function() {
// state = [ resolved | rejected ]
state = stateString;
// [ reject_list | resolve_list ].disable; progress_list.lock
}, tuples[ i ^ 1 ][ 2 ].disable, tuples[ 2 ][ 2 ].lock );
}
// deferred[ resolve | reject | notify ]
deferred[ tuple[0] ] = function() {
deferred[ tuple[0] + "With" ]( this === deferred ? promise : this, arguments );
return this;
};
deferred[ tuple[0] + "With" ] = list.fireWith;
});
// Make the deferred a promise
promise.promise( deferred );
// Call given func if any
if ( func ) {
func.call( deferred, deferred );
}
// All done!
return deferred;
},

Deferred: function( func ) {
var tuples = [
// action, add listener, listener list, final state
],
state = "pending",
promise = {
state: function() {
return state;
},
always: function() {
deferred.done( arguments ).fail( arguments );
return this;
},
if ( returned && jQuery.isFunction( returned.promise ) ) {

if ( returned && jQuery.isFunction( returned.promise ) ) {
returned.promise()
.done( newDefer.resolve )
.fail( newDefer.reject )
.progress( newDefer.notify );
} else {
newDefer[ tuple[ 0 ] + "With" ]( this === promise ?
newDefer.promise() : this, fn ? [ returned ] : arguments );
}
});
});
fns = null;
}).promise();
},
// Get a promise for this deferred
// If obj is provided, the promise aspect is added to the object
promise: function( obj ) {
return obj != null ? jQuery.extend( obj, promise ) : promise;

.fail( newDefer.reject )
.progress( newDefer.notify );
} else {
newDefer[ tuple[ 0 ] + "With" ]( this === promise ?
newDefer.promise() : this, fn ? [ returned ] : arguments );
}
});
});
fns = null;
}).promise();
},
// Get a promise for this deferred
// If obj is provided, the promise aspect is added to the object
promise: function( obj ) {
return obj != null ? jQuery.extend( obj, promise ) : promise;
}
},
deferred = {};

$.Deferred(function(dfd){
dfd
.done(function(){
$('#foo').fadeIn();
})
.done(function(){
$('#bar').fadeOut();
});
}).resolved();
$.Deferred(function(dfd){
dfd
.then(function(){
$('#foo').fadeIn();
})
.then(function(){
$('#bar').fadeOut();
});
}).resolved();

done
• deferred 對象始終是同⼀一個
• done 定義的 callback 都在同⼀一個 stack list
• resolve 之後 callbacks 是近乎同時呼叫
• 不應該預期 callbacks 會照順序執⾏行

then
• 每次都會建構⼀一個新的 deferred 物件
• then 定義的 callback 都是在⼀一個獨⽴立的 callbacks list
• 順序呼叫多次不同 deferred 物件的 resolved
• 預期是循序執⾏行

再推薦兩本必須看完的書

Eloquent
JavaScript
2nd edition

⼈人不⼀一定要⾛走出⾃自⼰己的舒適圈

⼈人不⼀一定要⾛走出⾃自⼰己的舒適圈
或許也可以考慮擴⼤大⾃自⼰己的舒適圈

前端⼯工程師⽕火熱加開中
http://jobs.kktix.cc

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