On several cloning (clone) methods in JavaScript

Reprint: https://www.cnblogs.com/zouhao/p/7278117.html

A: In JavaScript, if the cloned object is a basic type, we can assign it directly:

1 var sStr = "Kingwell"; 2 var cStr = sstr;3 alert (cStr);//output KINGWELL4 SSTR = "ABC"; 5 alert (CSTR);//output Kingwell;

When you assign a value to another variable, the value of that variable is not affected when it is changed.

Two: If it's not the basic type, it's all different:

1 var aarr = [0,1,2,3];2 var m = aarrr;3 alert (m);//Output 1,2,34 aarr=[3,2,1,0];5 alert (m);//output 3,2,1,0; This value is changed because M is just a reference to Aarr, If the value of Aarr is changed, then M will change accordingly.

If we want to clone an array, the simplest way:

1 var aarr = [0,1,2,3];2 var m = aarr.slice (0); 3 Aarr = [3,2,1,0];4 alert (m);//output 0,1,2,3, while the value in Aarr has changed, but because the slice method has been created A new array.

We can create a function to clone all objects:

1 function Clone (obj) {2     var o; 3     if (typeof obj = = "Object") {4         if (obj = = = null) {5             o = null; 6         } else {7             if (obj instanceof Array) {8                 o = []; 9                 for (var i = 0, len = obj.length; i < Len; i++) {                     O.push (Clone (Obj[i))),                 }12             } else {                 16 o = {};14 for                 (var j in obj) {o[j]                     = Clone (Obj[j]);                 }17             }18         }19     } else {         o = obj;21     }22     return o;23}

Three: node cloning:

1 var p = document.getelementsbytagname ("P") [0];2 var cp = P.clonenode ();//Clone P node 3 var cp = P.clonenode (TRUE);//clone P node, deep clone, Clones the node and the child content underneath the node.

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Source: http://www.cnblogs.com/snowinmay/p/3853425.html

There is no direct way to provide object cloning in JavaScript. So when you change object B in the code below, it changes the object A.

{K1:1, K2:2, K3:3}= a; b4;      

If you want to change only B and keep a constant, you need to copy object A.

Object copying with jquery

In the case of jquery, jquery's own extend method can be used to implement object replication.

{K1:1, K2:2, K3:3}{}; $.  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=(ThisinstanceofArray)?[]:{};For(attrInchThis){If(!obj.hasOwnProperty(attr))Continue; Copy[attr]=(typeofThis[I]=="Object"[attr]. Clone (): Obj[attr;  return copy;} ;a = {k1:1:2 :3};b = a. Clone            

The following example is considered more comprehensive and applies to deep copy of most objects.

functionClone(obj){Handle the 3 simple types, and null or undefinedIf(Null= = obj||"Object"!=typeof obj)return obj;Handle DateIf(objinstanceofDate){var copy=NewDate(); Copy.SetTime(obj.GetTime());return copy;}Handle ArrayIf(objinstanceofArray){var copy=[];For(var i=0,var len= obj. length; I< Len;++i){Copy[I]=Clone(obj[I]);}return copy;}Handle ObjectIf(objinstanceofObject){var copy={};For(var attrIn obj) { if (obj.  hasOwnProperty(attr)) copy[attr] = clone(obj[attr]); } return copy; } throw new Error("Unable to copy obj! Its type isn ' t supported. ); }< /c6> 

Classification:Java Script

On several cloning (clone) methods in JavaScript