Tips and pitfalls for JavaScript objects

3 method methods for creating objects 1

Directly create

var obj = {            name: "Mike",            Age:10        }

Method 2

Create with new

var ob = new Date ();

Method 3

ECMAScript5 has a new method Object.create ()

In fact, the method is to inherit an object

var obj = {            name: "Mike",            age:10        };        var newobj = object.create (obj);        Console.log (Newobj.name);

Some tricks and pitfalls

1

var a = {            name: "Mike",            Name: "John"        }        Console.log (a["name"]);

Accidentally writing a property name as a result is John, which means that when a property name is encountered. According to the last occurrence, note that when you start using strict, you will get an error.

2

var a = {};        a.x = 1;        var p = object.create (a);        P.Y = 2;        Console.log (p.x);

When you access the object's properties, he will continue to look up along the prototype chain,

3

var a = {};        a.x = 1;        var p = object.create (a);        P.Y = 2;        Console.log ("X" in P); True

There is no such attribute in an object if it is inherited.

4

var a = {};        a.x = 1;        var p = object.create (a);        P.Y = 2;        Console.log ("X" in P); True        Console.log (P.hasownproperty ("X"));//false

Check your own properties

5

var a = {            x:1,            get Getx () {return this.x;},            set Setx (ARG) {                return this.x = arg;            }        }        Console.log (a.x);        a.x = +;        Console.log (a.x);

Property can be set read-only, read/s Write

6

var a = {            x:1,            get Getx () {return this.x;},            set Setx (ARG) {                return this.x = arg;            }        }        Object.freeze (a);        a.x = +;        Console.log (a.x); 1

Freezing an object to ensure that the object's closeness is not compromised

Tips and pitfalls for JavaScript objects