JavaScript if in array

Use JavaScript includes() method to check if the value in Array. This method returns true if an array contains a specified value otherwise returns false if the value is not found.

array.includes(element, start)

Note: The includes() method is case sensitive.

Simple example code check if string is in array js.

<!DOCTYPE html>
<html>
<body>

  <script>

    var colors = ["red", "blue", "green"];
    var hasRed = colors.includes("red"); 
    var hasYellow = colors.includes("yellow"); 

    console.log(hasRed)
    console.log(hasYellow)

  </script>

</body>
</html>

Output:

You can also use Array#indexOf, which is less direct, but doesn’t require polyfills for outdated browsers.

console.log(['joe', 'jane', 'mary'].indexOf('jane') >= 0); //true

Many frameworks also offer similar methods:

jQuery: $.inArray(value, array, [fromIndex])
Underscore.js: _.contains(array, value) (also aliased as _.include and _.includes)
Dojo Toolkit: dojo.indexOf(array, value, [fromIndex, findLast])
Prototype: array.indexOf(value)
MooTools: array.indexOf(value)
MochiKit: findValue(array, value)
MS Ajax: array.indexOf(value)
Ext: Ext.Array.contains(array, value)
Lodash: _.includes(array, value, [from]) (is _.contains prior 4.0.0)
Ramda: R.includes(value, array)

Note: that some frameworks implement this as a function, while others add the function to the array prototype.

Do comment if you have any doubts or suggestions on this JS Array topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version

Rohit

Degree in Computer Science and Engineer: App Developer and has multiple Programming languages experience. Enthusiasm for technology & like learning technical.

JavaScript if in array | Example code