高手提领之 Douglas Crockford: "Advanced JavaScript"

来源：互联网发布：windows10系统优化编辑：程序博客网时间：2024/05/21 06:13

视频地址：http://video.yahoo.com/watch/111585/1027823
PPT下载：http://yuiblog.com/assets/crockford/advancedjavascript.zip

关于闭包（Closure）

Flexible, but Why we do that?

////////////////////////////////////////

Regular Singleton:

var singleton = {

firstMethod: function (a, b) {

...

secondMethod: function (c) {

...

}

};

////////////////////////////////////////

For Private Variables:

var singleton = function () {

var privateVariable;

function privateFunction(x) {

...privateVariable...

}

return {

firstMethod: function (a, b) {

...privateVariable...

secondMethod: function (c) {

...privateFunction()...

}

};

}();

////////////////////////////////////////

Return Private Object:

function powerConstructor() {

var that = object(oldObject),

privateVariable;

function privateFunction(x) {}

that.firstMethod = function (a, b) {

...privateVariable...

};

that.secondMethod = function (c) {

...privateFunction()...

};

return that;

}

////////////////////////////////////////

Regular Inheritance:

function Gizmo(id) {

this.id = id;

}

Gizmo.prototype.toString = function () {

return "gizmo " + this.id;

};

function Hoozit(id) {

this.id = id;

}

Hoozit.prototype = new Gizmo();

Hoozit.prototype.test = function (id) {

return this.id === id;

};

////////////////////////////////////////

Inheritance save code:

function gizmo(id) {

return {

id: id,

toString: function () {

return "gizmo " +this.id;

}

};

}

function hoozit(id) {

var that = gizmo(id);

that.test = function (testid) {

return testid === this.id;

};

return that;

}

////////////////////////////////////////

Private Property:

function gizmo(id) {

return {

toString: function () {

return "gizmo " + id;

}

};

}

function hoozit(id) {

var that = gizmo(id);

that.test = function (testid) {

return testid === id;

};

return that;

}

////////////////////////////////////////

Protected Property:

function gizmo(id, secret) {

secret = secret || {};

secret.id = id;

return {

toString: function () {

return "gizmo " + secret.id;

};

}

function hoozit(id) {

var secret = {}, /*final*/

that = gizmo(id, secret);

that.test = function (testid) {

return testid === secret.id;

};

return that;

}

////////////////////////////////////////

Call Super Function:

function hoozit(id) {

var secret = {},

that = gizmo(id, secret),

super_toString = that.toString;

that.test = function (testid) {

return testid === secret.id;

};

that.toString = function () {

return super_toString.apply(that, []);

};

return that;

}

高手提领 之 Douglas Crockford: "Advanced JavaScript"

高手提领之 Douglas Crockford: "Advanced JavaScript"