Introduction to using Object.create() to create objects in JavaScript_javascript skills

For object creation, in addition to using literals and the new operator, in the ECMAScript 5 standard, you can also use Object.create(). The Object.create() function accepts 2 objects as parameters: the first object is required and represents the prototype of the created object; the second object is optional and is used to define various properties of the created object (for example, writable , enumerable).

Copy code The code is as follows:

var o = Object.create({x:1, y:7});
console.log(o);//Object {x=1, y=7}
console.log(o.__proto__);//Object {x=1, y=7}

Calling Object.create() with null as the first argument will generate an object without a prototype, which will not have any basic Object properties (for example, since there is no toString() method, using operations on this object symbol will throw an exception):

Copy code The code is as follows:

var o2 = Object.create(null);
console.log("It is " o2);//Type Error, can't convert o2 to primitive type

For browsers that only support the ECMAScript 3 standard, you can use Douglas Crockford’s method to perform the Object.create() operation:

Copy code The code is as follows:

if (typeof Object.create !== 'function') {
Object.create = function (o) {
         function F() {}
          F.prototype = o;
          return new F();
};
}
newObject = Object.create(oldObject);