Js method of changing the original array and an array of solutions to change the original

Change the original array method

• pop (): Delete the last element of the array, and returns that element
• After addition array length in the end of the array element, and returns the updated: push ()
• shift (): Removes the first element of the array, and returns that element
• Array length after the first add elements in the array, and returns updated: unshift ()
• sort (): Sort of an array (ASCII character carried out by sorting), callback functions can be added according to the rules you want to sort
• reverse (): Array Reverse
• splice (index, howmany, new data): returns the removed elements consisting of arrays.

Solution to change the original array

BACKGROUND: a need equal the original array and the array, and does not affect the original array when the array operation process: deep copy.

var A = [. 1, 2,. 3 ];
 // this time need b is equal to a, but b is changed, does not affect A 

// method, Slice () 
var B1 = a.slice (); 

// Method II. the concat () 
var B2 = [] .concat (A); 

// method three, the JSON.parse (the JSON.stringify ()) 
var B3 = the JSON.parse (the JSON.stringify (A)); 

// method IV, handwritten The method of deep copy 
var the deepCopy = function (obj) {
　　IF ( typeof ! obj == 'Object') return ;
　　var newobj obj = the instanceof the Array? []: {};
　　for ( var key in obj) {
　　　　if (obj.hasOwnProperty(key)) {
　　　　　　newObj[key] = typeof obj[key] === 'object' ? deepCopy(obj[key]) : obj[key];
　　　　}
　　}
　　return newObj;
}
var b4 = deepCopy(a);