Deep copies of arrays and objects

One, deep copy of the array

　　var arr = ["One", "one", "three"];

var arrcopy = arr;

ARRCOPY[1] = "Test";

Console.log (arr); //["One", "Test", "three"]

Console.log (arrcopy); //["One", "Test", "three"]

1. If you assign an array to another array, change one and the other will change, which is a shallow copy of the array.

2. Solution: Using the slice and concat methods of arrays, both methods produce a new array without altering the original array.

　　　　var arr = ["One", "one", "three"];

var arrcopy = arr.slcie (0); //Arrcopy = Arr.concat ();

ARRCOPY[1] = "Test";

Console.log (arr); //["One", " One", "three"]

Console.log (arrcopy); //["One", "Test", "three"]

Second, deep copy of the object

　　var json = {name: "AAA", age:12};

var jsoncopy = json;

Jsoncopy.name = "BBB";

Console.log (JSON); //{name: "BBB", Age:12}

Console.log (jsoncopy); //{name: "BBB", Age:12}

1. Similarly, objects such as direct assignment are also shallow copies .

2. Solution: It is to iterate over the object's properties and assign it to a new object.

　　　　var json = {name: "AAA", age:12};

var jsoncopy = new Object ();

Jsoncopy.name = Json.name;

Jsoncopy.age = Json.age;

Jsoncopy.name = "BBB";

Console.log (JSON); //{name: "AAA", Age:12}

Console.log (jsoncopy); //{name: "BBB", Age:12}

　　

　　var deepcopy = function (source) {
var result={};
for (var key in source) {
Result[key] = typeof source[key]=== ' object '? Deepcopy (Source[key]): Source[key];
}
return result;
}

Deep copies of arrays and objects