JS in map traversal array

Source: Internet
Author: User

mapThe method iterates through each element of an algebraic group and processes each element according to the callback function, and finally returns a new array. Note that this method does not change the original array .

In our case, the callback function has only one parameter, the value (parameter) of the element in the array, val but in fact, your callback function can also support multiple parameters, such as: The index of the element, the index original array arr .

Example: Use the map method to oldArray add 3 to each item in, and newArray save them in. oldArrayshould not be changed.

var oldarray = [1,2,3,4,5];

var NewArray = Oldarray.map (function (w) {

return w+3;


The output is: [4,5,6,7,8]

JS in map traversal array

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