How JS traverses arrays and expands elements

This article mainly shows you "JS how to traverse the array and expand the elements", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "JS how to traverse the array and expand the elements" this article.

1. Map () calls the specified callback function on each element of the array and returns the array containing the results.

Var a = [30 value 40 50]; function f (value) {return value*2;} var a1=a.map (f); console.log (A1)

2. ForEach () can call each element of the array and pass the element to the callback function.

Var a = [20J 30J 40]; function f (value) {console.log (value*2);} a.forEach (f)

3. For in statement to traverse the array.

The variable I represents the subscript of the array, and a [I] is the element value that can read the specified subscript.

Var a = [10Jet 20jue 30]; for (var i in a) {a [I] = 2yoga [I];} console.log (a); this is all the content of the article "how JS traverses arrays and expands elements". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!