How to check if a string array contains one string in JavaScript? [duplicate]

Question

I have a string array and one string. I'd like to test this string against the array values and apply a condition the result - if the array contains the string do "A", else do "B".

How can I do that?

Answer 1

There is an indexOf method that all arrays have (except Internet Explorer 8 and below) that will return the index of an element in the array, or -1 if it's not in the array:

if (yourArray.indexOf("someString") > -1) { //In the array! } else { //Not in the array } 

If you need to support old IE browsers, you can polyfill this method using the code in the MDN article.

Answer 2

You can use the indexOfmethod and "extend" the Array class with the method contains like this:

Array.prototype.contains = function(element){ return this.indexOf(element) > -1; }; 

with the following results:

["A", "B", "C"].contains("A") equals true

["A", "B", "C"].contains("D") equals false

Answer 3

var stringArray = ["String1", "String2", "String3"]; return (stringArray.indexOf(searchStr) > -1) 

Answer 4

Create this function prototype:

Array.prototype.contains = function ( needle ) { for (var i in this) { // Loop through every item in array if (this[i] == needle) return true; // return true if current item == needle } return false; } 

and then you can use following code to search in array x

if (x.contains('searchedString')) { // do a } else { // do b } 

Answer 5

This will do it for you:

function inArray(needle, haystack) { var length = haystack.length; for(var i = 0; i < length; i++) { if(haystack[i] == needle) return true; } return false; } 

I found it in Stack Overflow question JavaScript equivalent of PHP's in_array().