check if array contains some array value javascript code example

Example 1: check if array has same values javascript

const allEqual = arr => arr.every(v => v === arr[0]);
allEqual([1,1,1,1]);  // true

Example 2: how to check if an array contains a number in javascript

// To check if an array contains a number
const ratings = [1,2,3,4,5];

let result = ratings.includes(4); 
console.log(result); // true

result = ratings.includes(6); 
console.log(result); // false