JavaScript - check if array of strings contains given string

In this article, we would like to show you how to check if an array of strings contains a given string using JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

var letters = ['a', 'b', 'c'];

var letter = 'b'; // string to search for

if (letters.indexOf(letter) > -1) {
    // do some action when string is in array e.g:
    console.log('The letter is in the array.');
} else {
    // do some action when string is not in array e.g:
    console.log('The letter is not in the array.');
}

Reusable function

In this example, we create a reusable arrow function to check if string is in the array.

// ONLINE-RUNNER:browser;

const isInArray = (array, string) => {
    if (array.indexOf(string) > -1) {
        return true;
    }
   return false;
};


// Usage example:

var letters = ['a', 'b', 'c'];

console.log(isInArray(letters, 'a')); // true
console.log(isInArray(letters, 'x')); // false

References

1. Array.prototype.indexOf() - JavaScript | MDN