Check if an Item Exists in an Array

Instead of using the indexOf() method to check if an element is in the array, you can use the includes() method. This makes your intent very clear:

let numbers = [1, 2, 3];

// LONGER FORM
const hasNumber1 = numbers.indexOf(1) > -1 // -> True

// SHORTHAND/CLEANER APPROACH
const hasNumber1 = numbers.includes(1)     // -> True

Source

https://medium.com/geekculture/20-javascript-snippets-to-code-like-a-pro-86f5fda5598e