這篇文章主要介紹“javascript的面向?qū)ο筇匦允鞘裁础保谌粘2僮髦校嘈藕芏嗳嗽趈avascript的面向?qū)ο筇匦允鞘裁磫栴}上存在疑惑,小編查閱了各式資料,整理出簡單好用的操作方法,希望對大家解答”javascript的面向?qū)ο筇匦允鞘裁础钡囊苫笥兴鶐椭〗酉聛恚埜【幰黄饋韺W(xué)習(xí)吧!

面向?qū)ο蟮娜蠡咎匦?/strong>
封裝(把相關(guān)的信息(無論數(shù)據(jù)或方法)存儲在對象中的能力)
繼承(由另一個(gè)類(或多個(gè)類)得來類的屬性和方法的能力)
多態(tài)(一個(gè)對象在不同情況下的多種形態(tài))
定義類或?qū)ο?/strong>
第一種:基于Object對象
var person = new Object();
person.name = "Rose";
person.age = 18;
person.getName = function () {
return this.name;
};
console.log(person.name);//Rose
console.log(person.getName);//function () {return this.name;}
console.log(person.getName());//Rose缺點(diǎn):不能創(chuàng)建多個(gè)對象。
第二種:基于字面量方式
var person = {
name : "Rose",
age : 18 ,
getName : function () {
return this.name;
}
};
console.log(person.name);//Rose
console.log(person.getName);//function () {return this.name;}
console.log(person.getName());//Rose優(yōu)點(diǎn):比較清楚的查找對象包含的屬性和方法;
缺點(diǎn):不能創(chuàng)建多個(gè)對象。
第三種:工廠模式
方式一:
function createPerson(name,age) {
var object = new Object();
object.name = name;
object.age = age;
object.getName = function () {
return this.name;
};
return object;
}
var person1 = createPerson("Rose",18);
var person2 = createPerson("Jack",20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName);//false//重復(fù)生成函數(shù),為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本優(yōu)點(diǎn):可以創(chuàng)建多個(gè)對象;
缺點(diǎn):重復(fù)生成函數(shù)getName(),為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本。
方式二:
function createPerson(name,age) {
var object = new Object();
object.name = name;
object.age = age;
object.getName = getName;
return object;
}
function getName() {
return this.name;
}
var person1 = createPerson("Rose",18);
var person2 = createPerson("Jack",20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName);//true//共享同一個(gè)函數(shù)優(yōu)點(diǎn):可以創(chuàng)建多個(gè)對象;
缺點(diǎn):從語義上講,函數(shù)getName()不太像是Person對象的方法,辨識度不高。
第四種:構(gòu)造函數(shù)方式
方式一:
function Person(name,age) {
this.name = name;
this.age = age;
this.getName = function () {
return this.name;
}
}
var person1 = new Person("Rose",18);
var person2 = new Person("Jack",20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName); //false//重復(fù)生成函數(shù),為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本優(yōu)點(diǎn):可以創(chuàng)建多個(gè)對象;
缺點(diǎn):重復(fù)生成函數(shù)getName(),為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本。
方式二:
function Person(name,age) {
this.name = name;
this.age = age;
this.getName = getName ;
}
function getName() {
return this.name;
}
var person1 = new Person("Rose",18);
var person2 = new Person("Jack",20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName); //true//共享同一個(gè)函數(shù)優(yōu)點(diǎn):可以創(chuàng)建多個(gè)對象;
缺點(diǎn):從語義上講,函數(shù)getName()不太像是Person對象的方法,辨識度不高。
第五種:原型方式
function Person() {
}
Person.prototype.name = 'Rose';
Person.prototype.age = 18;
Person.prototype.getName = function () {
return this.name;
};
var person1 = new Person();
var person2 = new Person();
console.log(person1.name);//Rose
console.log(person2.name);//Rose//共享同一個(gè)屬性
console.log(person1.getName === person2.getName);//true//共享同一個(gè)函數(shù)缺點(diǎn):它省略了為構(gòu)造函數(shù)傳遞初始化參數(shù),這在一定程序帶來不便;另外,最主要是當(dāng)對象的屬性是引用類型時(shí),它的值是不變的,總是引用同一個(gè)外部對象,所有實(shí)例對該對象的操作都會影響其它實(shí)例:
function Person() {
}
Person.prototype.name = 'Rose';
Person.prototype.age = 18;
Person.prototype.lessons = ["語文","數(shù)學(xué)"];
Person.prototype.getName = function () {
return this.name;
};
var person1 = new Person();
person1.lessons.push("英語");
var person2 = new Person();
console.log(person1.lessons);//["語文", "數(shù)學(xué)", "英語"]
console.log(person2.lessons);//["語文", "數(shù)學(xué)", "英語"]//person1修改影響了person2第六種:構(gòu)造函數(shù)+原型方式(推薦)
function Person(name,age) {
this.name = name;
this.age = age;
}
Person.prototype.getName = function () {
return this.name;
};
var person1 = new Person('Rose', 18);
var person2 = new Person('Jack', 20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName);//true//共享原型中定義的方法缺點(diǎn):屬性定義在構(gòu)造函數(shù)內(nèi),方法定義在構(gòu)造函數(shù)外,與面向?qū)ο蟮姆庋b思想不符。
第七種:構(gòu)造函數(shù)+動態(tài)原型方式(推薦)
方式一:
function Person(name,age) {
this.name = name;
this.age = age;
if (typeof Person._getName === "undefined"){
Person.prototype.getName = function () {
return this.name;
};
Person._getName = true;
}
}
var person1 = new Person('Rose', 18);
var person2 = new Person('Jack', 20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName);//true//共享原型中定義的方法方式二:
function Person(name,age) {
this.name = name;
this.age = age;
if (typeof this.getName !== "function"){
Person.prototype.getName = function () {
return this.name;
};
}
}
var person1 = new Person('Rose', 18);
var person2 = new Person('Jack', 20);
console.log(person1.name);//Rose
console.log(person2.name);//Jack
console.log(person1.getName === person2.getName);//true//共享原型中定義的方法對象屬性的擴(kuò)展及刪除
Javascript的對象可以使用 '.' 操作符動態(tài)的擴(kuò)展其屬性,可以使用 'delete' 關(guān)鍵字或?qū)傩缘闹翟O(shè)置為 'undefined' 來刪除屬性。
function Person(name,age) {
this.name = name;
this.age = age;
if (typeof Person._getName === "undefined"){
Person.prototype.getName = function () {
return this.name;
};
Person._getName = true;
}
}
var person = new Person("Rose",18);
person.job = 'Engineer';//添加屬性
console.log(person.job);//Engineer
delete person.job;//刪除屬性
console.log(person.job);//undefined//刪除屬性后值為undefined
person.age = undefined;//刪除屬性
console.log(person.age);//undefined//刪除屬性后值為undefined對象屬性類型
數(shù)據(jù)屬性
特性:
[configurable]:表示能否使用delete操作符刪除從而重新定義,或能否修改為訪問器屬性。默認(rèn)為true;
[enumberable]:表示是否可通過for-in循環(huán)返回屬性。默認(rèn)true;
[writable]:表示是否可修改屬性的值。默認(rèn)true;
[value]:包含該屬性的數(shù)據(jù)值。讀取/寫入都是該值。默認(rèn)為undefined;如上面實(shí)例對象person中定義了name屬性,其值為'My name',對該值的修改都反正在這個(gè)位置
function Person(name,age) {
this.name = name;
this.age = age;
if (typeof Person._getName === "undefined"){
Person.prototype.getName = function () {
return this.name;
};
Person._getName = true;
}
}
var person = new Person("Rose",18);
Object.defineProperty(person,"name",{configurable:false,writable:false});
person.name = "Jack";
console.log(person.name);//Rose//重新賦值無效
delete person.name;
console.log(person.name);//Rose//刪除無效注意:
一旦將configurable設(shè)置為false,則無法再使用defineProperty將其修改為true(執(zhí)行會報(bào)錯(cuò):cannot redefine property : propertyName)
function Person(name,age) {
this.name = name;
this.age = age;
if (typeof Person._getName === "undefined"){
Person.prototype.getName = function () {
return this.name;
};
Person._getName = true;
}
}
var person = new Person("Rose",18);
Object.defineProperty(person,"name",{configurable:false,writable:false});
person.name = "Jack";
console.log(person.name);//Rose//重新賦值無效
delete person.name;
console.log(person.name);//Rose//刪除無效
Object.defineProperty(person,"name",{configurable:true,writable:true});//Cannot redefine property: name訪問器屬性
特性:
[configurable]:是否可通過delete操作符刪除重新定義屬性;
[numberable]:是否可通過for-in循環(huán)查找該屬性;
[get]:讀取屬性時(shí)調(diào)用,默認(rèn):undefined;
[set]:寫入屬性時(shí)調(diào)用,默認(rèn):undefined;
訪問器屬性不能直接定義,必須使用defineProperty()或defineProperties來定義:如下
function Person(name,age) {
this.name = name;
this._age = age;
if (typeof Person._getName === "undefined"){
Person.prototype.getName = function () {
return this.name;
};
Person._getName = true;
}
}
var person = new Person("Rose",18);
Object.defineProperty(person,"age",{
get:function () {
return this._age;
},
set:function (age) {
this._age = age;
}});
person.age = 20;
console.log(person.age);//20//person.age=20是使用set方法將20賦值給_age,person.age是使用get方法將_age的讀取出來
console.log(person._age);//20獲取所有的屬性和屬性的特性
使用Object.getOwnPropertyNames(object)方法可以獲取所有的屬性;
使用Object.getOwnPropertyDescriptor(object,property)方法可以取得給定屬性的特性;
function Person(name,age) {
this.name = name;
this._age = age;
if (typeof Person._getName === "undefined"){
Person.prototype.getName = function () {
return this.name;
};
Person._getName = true;
}
}
var person = new Person("Rose",18);
Object.defineProperty(person,"age",{
get:function () {
return this._age;
},
set:function (age) {
this._age = age;
}});
console.log(Object.getOwnPropertyNames(person));//["name", "_age", "age"]
console.log(Object.getOwnPropertyDescriptor(person,"age"));//{enumerable: false, configurable: false, get: function, set: function}對于數(shù)據(jù)屬性,可以取得:configurable,enumberable,writable和value;
對于訪問器屬性,可以取得:configurable,enumberable,get和set;
繼承機(jī)制實(shí)現(xiàn)
對象冒充
function Father(name) {
this.name = name ;
this.getName = function () {
return this.name;
}
}
function Son(name,age) {
this._newMethod = Father;
this._newMethod(name);
delete this._newMethod;
this.age = age;
this.getAge = function () {
return this.age;
}
}
var father = new Father("Tom");
var son = new Son("Jack",18);
console.log(father.getName());//Tom
console.log(son.getName());//Jack//繼承父類getName()方法
console.log(son.getAge());//18多繼承(利用對象冒充可以實(shí)現(xiàn)多繼承)
function FatherA(name) {
this.name = name ;
this.getName = function () {
return this.name;
}
}
function FatherB(job) {
this.job = job;
this.getJob = function () {
return this.job;
}
}
function Son(name,job,age) {
this._newMethod = FatherA;
this._newMethod(name);
delete this._newMethod;
this._newMethod = FatherB;
this._newMethod(job);
delete this._newMethod;
this.age = age;
this.getAge = function () {
return this.age;
}
}
var fatherA = new FatherA("Tom");
var fatherB = new FatherB("Engineer");
var son = new Son("Jack","Programmer",18);
console.log(fatherA.getName());//Tom
console.log(fatherB.getJob());//Engineer
console.log(son.getName());//Jack//繼承父類FatherA的getName()方法
console.log(son.getJob());//Programmer//繼承父類FatherB的getJob()方法
console.log(son.getAge());//18call()方法
function Father(name) {
this.name = name ;
this.getName = function () {
return this.name;
}
}
function Son(name,job,age) {
Father.call(this,name);
this.age = age;
this.getAge = function () {
return this.age;
}
}
var father = new Father("Tom");
var son = new Son("Jack","Programmer",18);
console.log(father.getName());//Tom
console.log(son.getName());//Jack//繼承父類getName()方法
console.log(son.getAge());//18多繼承(利用call()方法實(shí)現(xiàn)多繼承)
function FatherA(name) {
this.name = name ;
this.getName = function () {
return this.name;
}
}
function FatherB(job) {
this.job = job;
this.getJob = function () {
return this.job;
}
}
function Son(name,job,age) {
FatherA.call(this,name);
FatherB.call(this,job);
this.age = age;
this.getAge = function () {
return this.age;
}
}
var fatherA = new FatherA("Tom");
var fatherB = new FatherB("Engineer");
var son = new Son("Jack","Programmer",18);
console.log(fatherA.getName());//Tom
console.log(fatherB.getJob());//Engineer
console.log(son.getName());//Jack//繼承父類FatherA的getName()方法
console.log(son.getJob());//Programmer//繼承父類FatherB的getJob()方法
console.log(son.getAge());//18apply()方法
function Father(name) {
this.name = name ;
this.getName = function () {
return this.name;
}
}
function Son(name,job,age) {
Father.apply(this,new Array(name));
this.age = age;
this.getAge = function () {
return this.age;
}
}
var father = new Father("Tom");
var son = new Son("Jack","Programmer",18);
console.log(father.getName());//Tom
console.log(son.getName());//Jack//繼承父類getName()方法
console.log(son.getAge());//18多繼承(利用apply()方法實(shí)現(xiàn)多繼承)
function FatherA(name) {
this.name = name ;
this.getName = function () {
return this.name;
}
}
function FatherB(job) {
this.job = job;
this.getJob = function () {
return this.job;
}
}
function Son(name,job,age) {
FatherA.apply(this,new Array(name));
FatherB.apply(this,new Array(job));
this.age = age;
this.getAge = function () {
return this.age;
}
}
var fatherA = new FatherA("Tom");
var fatherB = new FatherB("Engineer");
var son = new Son("Jack","Programmer",18);
console.log(fatherA.getName());//Tom
console.log(fatherB.getJob());//Engineer
console.log(son.getName());//Jack//繼承父類FatherA的getName()方法
console.log(son.getJob());//Programmer//繼承父類FatherB的getJob()方法
console.log(son.getAge());//18原型鏈方法
function Father() {
}
Father.prototype.name = "Tom";
Father.prototype.getName = function () {
return this.name;
};
function Son() {
}
Son.prototype = new Father();
Son.prototype.age = 18;
Son.prototype.getAge = function () {
return this.age;
};
var father = new Father();
var son = new Son();
console.log(father.getName());//Tom
console.log(son.getName());//Tom//繼承父類FatherA的getName()方法
console.log(son.getAge());//18混合方式(call()+原型鏈)
function Father(name) {
this.name = name;
}
Father.prototype.getName = function () {
return this.name;
};
function Son(name,age) {
Father.call(this,name);
this.age = age;
}
Son.prototype = new Father();
Son.prototype.getAge = function () {
return this.age;
};
var father = new Father("Tom");
var son = new Son("Jack",18);
console.log(father.getName());//Tom
console.log(son.getName());//Jack//繼承父類Father的getName()方法
console.log(son.getAge());//18多態(tài)機(jī)制實(shí)現(xiàn)
function Person(name) {
this.name = name;
if (typeof this.getName !== "function"){
Person.prototype.getName = function () {
return this.name;
}
}
if (typeof this.toEat !== "function"){
Person.prototype.toEat = function (animal) {
console.log( this.getName() + "說去吃飯:");
animal.eat();
}
}
}
function Animal(name) {
this.name = name;
if (typeof this.getName !== "function"){
Animal.prototype.getName = function () {
return this.name;
}
}
}
function Cat(name) {
Animal.call(this,name);
if (typeof this.eat !== "function"){
Cat.prototype.eat = function () {
console.log(this.getName() + "吃魚");
}
}
}
Cat.prototype = new Animal();
function Dog(name) {
Animal.call(this,name);
if (typeof this.eat !== "function"){
Dog.prototype.eat = function () {
console.log(this.getName() + "啃骨頭");
}
}
}
Dog.prototype = new Animal();
var person = new Person("Tom");
person.toEat(new Cat("cat"));//Tom說去吃飯:cat吃魚
person.toEat(new Dog("dog"));//Tom說去吃飯:dog啃骨頭到此,關(guān)于“javascript的面向?qū)ο筇匦允鞘裁础钡膶W(xué)習(xí)就結(jié)束了,希望能夠解決大家的疑惑。理論與實(shí)踐的搭配能更好的幫助大家學(xué)習(xí),快去試試吧!若想繼續(xù)學(xué)習(xí)更多相關(guān)知識,請繼續(xù)關(guān)注創(chuàng)新互聯(lián)成都做網(wǎng)站網(wǎng)站,小編會繼續(xù)努力為大家?guī)砀鄬?shí)用的文章!
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