Deep understanding of object copying in JavaScript (objects clone) _ Basics

JavaScript does not directly provide a method for object replication (the object clone). So when you change object B in the following code, you change object A.

A = {k1:1, k2:2, k3:3};

b = A;

B.K2 = 4;

If you just want to change B and keep a unchanged, you need to copy object A.

Using jquery for Object replication

With jquery, the Extend method of jquery can be used to replicate objects.

A = {k1:1, k2:2, k3:3};

b = {};

$.extend (B,a);

Customizing the Clone () method to implement object replication

The following method is the basic idea of object replication.

Object.prototype.clone = function () {
 var copy = (this instanceof Array)? [] : {};
 For (attr in this) {
  if (!obj.hasownproperty (attr)) continue;
  COPY[ATTR] = (typeof this[i] = = "Object")? Obj[attr].clone (): obj[attr];
 } 
 return copy;


A = {k1:1, k2:2, k3:3};
b = A.clone ();

The following example is considered more comprehensive and is suitable for deep replication of most objects (Deep copy).

function Clone (obj) {
  //Handle The 3 simple types, and null or undefined
  if (null = obj | | "Object"!= typeof obj) return to obj;

  Handle Date
  if (obj instanceof date) {
    var copy = new Date ();
    Copy.settime (Obj.gettime ());
    return copy;
  }

  Handle array
  if (obj instanceof array) {
    var copy = [];
    for (var i = 0, var len = Obj.length i < len; ++i) {
      Copy[i] = Clone (obj[i));
    return copy;
  }

  Handle Object
  if (obj instanceof object) {
    var copy = {};
    for (var attr in obj) {
      if (Obj.hasownproperty (attr)) copy[attr] = Clone (obj[attr));
    return copy;
  }

  throw new Error ("Unable to copy obj! Its type isn ' t supported. ');

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