{"use strict";}!function strict() { }();"use strict";var nAme;nEme = 17; // ReferenceError"use strict";var obj1 = {};obj1.x = 9; //TypeError
var obj2 = {get x(){return 17;}};obj2.x = 5; // TypeError
var fixed = {};Object.preventExtensions(fixed);"use strict";delete Object.prototype; // TypeError"use strict";var o = {p:1, p:2};function sum(a, a, c) { }var a = 0o10;parseInt(a);"use strict";var sum = 015 + // SyntaxError 197 + 142;!function() {"use strict";
}();"use strict";var x = 17;{ x; // x mean obj.x or var x? it will make engine can not process optimization. }
console.log(x); //x will be create.}
var x = 17;var evalX = eval("'use strict'; var x = 42; x"); //this x !== var x=17console.assert(x === 17);console.assert(evalX === 42);function strict1(str) { return eval(str); // str will be treated as strict mode code}function strict2(f, str) { return f(str); // not eval(...): str is strict if and only // if it invokes strict mode}function nonstrict(str) { return eval(str); // str is strict if and only // if it invokes strict mode}
strict1("'Strict mode code!'");nonstrict("'Non-strict code.'");'use strict';var a={x:10};delete a.x; // It can delete
var x;delete x; // SyntaxError
eval('var y; delete y;'); // SyntaxError
"use strict";eval = 17;arguments++;++eval;var obj = { set p(arguments) { } };var eval;function x(eval) { }function arguments() { }var y = function eval() { };function f(a){ a = 42; //a 改變，但是函數的arguments仍是f(17);}var pair = f(17);console.assert(pair[0] === 42);console.assert(pair[1] === 17);"use strict";var f = function() { return arguments.callee; };f(); // TypeError'use strict';function fun() { return this; }console.assert(fun() === undefined);console.assert(fun.call(2) === 2);console.assert(fun.apply(null) === null);console.assert(fun.call(undefined) === undefined);console.assert(fun.bind(true)() === true);function restricted(){ restricted.caller; // TypeError restricted.arguments; // TypeError}function privilegedInvoker(){ return restricted();}privilegedInvoker();function fun(a, b) { var v = 12; return arguments.caller; // throws a TypeError}implements, interface, let, package, private, protected, public, static, yieldfunction package(protected){ // !!! var implements; // !!!
interface: // !!! { break interface; // !!! }
function private() { } // !!!} function f() { } // SyntaxError function f2() { } // SyntaxError
function baz() { // ok function eit() { } // ok}Every application has a single root scope. All other scopes are descendant scopes of the root scope. Scopes provide separation between the model and the view, via a mechanism for watching the model for changes. They also provide event emission/broadcast and subscription facility.一個ng-app只會有一個 $rootScope，所有的 $scope 都是 $rootScope 的child scope。文件特別把angular的emission/broadcast機制放在定義，這也代表事件處理是 $rootScope 很重要的操作。
// firing an event upwards
$scope.$emit('myCustomEvent', 'Data to send');
// firing an event downwards
$scope.$broadcast('myCustomEvent', {
someProp: 'Sending you an Object!' // send whatever you want
});
// listen for the event in the relevant $scope
$scope.$on('myCustomEvent', function (event, data) {
console.log(data); // 'Data to send'
});
$scope.$parent.$broadcast('myevent', 'Some data');
<div ng-controller="ParentCtrl as parent" class="ng-scope">
// ParentCtrl
<div ng-controller="SiblingOneCtrl as sib1" class="ng-scope">
// SiblingOneCtrl
</div>
<div ng-controller="SiblingTwoCtrl as sib2" class="ng-scope">
// SiblingTwoCtrl
<div ng-controller="ChildCtrl as child" class="ng-scope">
// ChildCtrl
</div>
</div>
</div>
app.controller('SiblingOneCtrl',
function SiblingOneCtrl ($rootScope) {
$rootScope.$on('rootScope:emit', function (event, data) {
console.log(data); // 'Emit!'
});
$scope.$on('rootScope:broadcast', function (event, data) {
console.log(data); // 'Broadcast!'
});
$rootScope.$on('rootScope:broadcast', function (event, data) {
console.log(data); // 'Broadcast!'
});
});
app.controller('ChildCtrl',
function ChildCtrl ($rootScope) {
$rootScope.$emit('rootScope:emit', 'Emit!'); // $rootScope.$on
$rootScope.$broadcast('rootScope:broadcast', 'Broadcast'); // $rootScope.$on && $scope.$on
});
function SuperType(){
this.property = true;
}
SuperType.prototype.getSuperValue = function (){
return this.property;
};
function SubType() {
this.subproperty = false;
}
//inherit from SuperType
SubType.prototype = new SuperType();
SubType.prototype.getSubValue = function () {
return this.subproperty;
};
var instance = new SubType();
window.console.log(instance.getSuperValue());Check out this Pen!
function person (){
this.age = 10;
this.name = "Kevin";
};
var p = new person();
console.log(p.age + ":" + p.name);
function person_closure (age, name) {
this.getName = function () {return name; };
this.setName = function (newName) {name = newName; };
this.getAge = function () {return age;};
this.setAge = function (newAge) {age = newAge;};
}
var p_c = new person_closure(10, "Kevin");
console.log(p_c.age + ":" + p_c.name);
console.log(p_c);
p_c = null;Check out this Pen!| 出現情況 | this 說明 | 範例程式 |
| 物件方法的呼叫 | 呼叫方法的物件 (Caller) |
var obj = new Object(); obj.id = "test"; obj.findThis = function(){ alert(this.id)}; obj.findThis(); // this is obj. |
| Global Function 呼叫 | window, strict mode is undefined. Caller is window |
function test(){ alert(this); } test(); |
| 使用 new產生一個 instance | 就是 這個物件本身 | function test(){ alert(this) } var o = new test(); //this is o |
| 使用
Apply, Call呼叫函數 帶入第一個參數值改變 Context. |
被改變的 Context值 | function test(){ alert(this.id); } var m = {id: "m"}; var n = {id: "n"}; var o = {id: "o"}; o.fn = test; o.fn.apply(m); // this is m o.fn.call(n); // this is n |
var arg = 1;
function funcTest() {
alert(arg);
var arg = 2;
}
funcTest();
function funcTest2() {
alert(arg);
//var arg = 2;
}
funcTest2();
Check out this Pen!YUI().use('event-key', function (Y) {
Y.one("body").on("key", function(e){
e.preventDefault();
alert("esc press");
location.href = "http://codepen.io";
}, "esc");
});
Check out this Pen!
JavaScript 在語言本身、模擬物件導向的開發中，this 都是很清楚的代表一個 instance。
把 this 搞複雜的原因，其實是瀏覽器特有的 DOM API。
像是 DOM Event、或像是 window.XMLHttpRequest 這樣的全域方法。
this 在對應的處理函式中都不會是所預期 instance。
這也是為什麼在 Y.on 或 Y.io 都有提供設定 context 的參數。
或者得自己去使用 call 或 apply 取執行 Handler、讓 Handler 正確處理。
如果今天開發的是沒有瀏覽器的 JavaScript，例如 Node.js,
this 通常是不會造成太大的困擾的 :)
on: {
viewload: function () {
api = this;
api.get(node).
one('form').on('submit', _handleSubmit, api);
// (1).api is the context
}
}
_handleSubmit = function (event) {
var _api = this; //(2) this is api from (1) context
_api.get(node).all('input');
_enableForm.call(_api, arg1, arg2);
//(3.1) this _api is context
_enableForm.apply(_api, [arg1, arg2]);
//(3.2) this _api is context
}
_api.confirm(message, callback);
//callback will need _api as context_api.confirm(message, Y.bind(callback. _api));
//callback will need _api as context
Deferred: function( func ) {
var doneList = jQuery.Callbacks( "once memory" ),
failList = jQuery.Callbacks( "once memory" ),
progressList = jQuery.Callbacks( "memory" ),
javascript:(function() {
function get_filetype(fmt_id) {
switch(fmt_id) {
case '5':
case '6':
case '34':
case '35':
return 'FLV';
case '18':
case '22':
case '37':
case '38':
case '82':
case '83':
case '84':
case '85':
return 'MP4';
case '43':
case '44':
case '45':
case '46':
case '100':
case '101':
case '102':
return 'WEBM';
default:
return 'unknown';
}
}
function get_video_url(fmt_stream_map,
chosen_fmt_id,
avail_fmt_ids) {
fmt_stream_map=unescape(fmt_stream_map);
if(avail_fmt_ids.indexOf(chosen_fmt_id)===0)
return
fmt_stream_map.substring(4,
fmt_stream_map.indexOf('&quality='));
if(avail_fmt_ids.indexOf(chosen_fmt_id)===avail_fmt_ids.length-1)
return
fmt_stream_map.substring(fmt_stream_map.lastIndexOf('http'),
fmt_stream_map.lastIndexOf('&quality='));
var pattern=new RegExp('&itag='+avail_fmt_ids[avail_fmt_ids.indexOf(chosen_fmt_id)-1]+',url=(.+?)&quality=');
return fmt_stream_map.match(pattern)[1];
}
(function main() {
var args=yt.playerConfig['args'];
var fmt_quality_list='';
var chosen_fmt_id=0;
var fmt_info=args['fmt_list'].split(',');
var fmt_resolution='';
var avail_fmt_ids=new Array(fmt_info.length);
for(var i in fmt_info) {
avail_fmt_ids[i]=fmt_info[i].split('/')[0];
fmt_resolution=fmt_info[i].split('/')[1];
fmt_quality_list+=(avail_fmt_ids[i]+' = '+fmt_resolution+' ('+get_filetype(avail_fmt_ids[i])+')\n');
}
loop: while(true) {
chosen_fmt_id=prompt('Please enter a format id.\n'+fmt_quality_list, avail_fmt_ids[0]);
if(chosen_fmt_id===null) {
return;
}
for(var i in avail_fmt_ids) {
if(chosen_fmt_id===avail_fmt_ids[i]) {
break loop;
}
}
}
window.open(get_video_url(args['url_encoded_fmt_stream_map'], chosen_fmt_id, avail_fmt_ids)+'&title='+document.getElementsByName('title')[0].content);
}());
}());
def _closed_captions_xml_to_srt(self, xml_string):
srt = ''
texts = re.findall(r'([^<]+) ', xml_string, re.MULTILINE)
# TODO parse xml instead of regex
for n, (start, dur_tag, dur, caption) in enumerate(texts):
if not dur: dur = '4'
start = float(start)
end = start + float(dur)
start = "%02i:%02i:%02i,%03i" %(start/(60*60), start/60%60, start%60, start%1*1000)
end = "%02i:%02i:%02i,%03i" %(end/(60*60), end/60%60, end%60, end%1*1000)
caption = unescapeHTML(caption)
caption = unescapeHTML(caption) # double cycle, intentional
srt += str(n+1) + '\n'
srt += start + ' --> ' + end + '\n'
srt += caption + '\n\n'
return srt