[[prototype]]: object
时间: 2023-04-28 13:02:15 浏览: 56
[[prototype]]是一个对象的内部属性,它指向该对象的原型。原型是一个对象,它包含了该对象的属性和方法。当我们访问一个对象的属性或方法时,如果该对象本身没有该属性或方法,那么就会去它的原型对象中查找。这种机制被称为原型链。在JavaScript中,所有的对象都有原型,除了Object.prototype。
相关问题
[[Prototype]] : Object
[[Prototype]] is a property that exists on all objects in JavaScript. It is an internal link to another object, known as the object's prototype. In other words, every object in JavaScript inherits properties and methods from a prototype object, which is used as a blueprint for the object's behavior.
When a property or method is called on an object, JavaScript first checks if the object itself has that property or method. If it doesn't, it looks up the prototype chain to see if the object's prototype has it. This prototype chain continues until the root object, Object.prototype, is reached.
For example, consider the following code:
```
let person = {
name: "John",
age: 30,
sayHello: function() {
console.log("Hello!");
}
};
let student = {
major: "Computer Science"
};
student.__proto__ = person;
console.log(student.name); // "John"
student.sayHello(); // "Hello!"
```
In this example, we create a person object with a name, age, and sayHello method. We then create a student object and set its prototype to be the person object. This means that the student object will inherit the properties and methods of the person object.
When we try to access the `name` property of the student object, JavaScript first checks if the student object has a `name` property. Since it doesn't, it looks up the prototype chain and finds the `name` property on the person object. Similarly, when we call the `sayHello` method on the student object, JavaScript looks up the prototype chain and finds the `sayHello` method on the person object.
Overall, [[Prototype]] is a powerful feature in JavaScript that allows for efficient and flexible object inheritance.
[[Prototype]] : Object中文意思
[[Prototype]]是JavaScript中一个内部属性,表示一个对象的原型。每个对象都有一个原型,可以通过原型链来访问原型的属性和方法。在JavaScript中,对象可以通过一个构造函数创建,每个构造函数都有一个原型对象,而实例对象通过原型链继承构造函数的原型对象。当访问一个对象的属性或方法时,如果当前对象没有该属性或方法,JavaScript会沿着原型链向上查找,直到找到该属性或方法或者到达原型链的末端。
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