JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr1 = [1, 2, 3, 4, 5];
var arr2 = [3, 10, 12, 4, 15];

function findCommon(arr1, arr2) {
    return arr1.filter(function (el) {
        return arr2.indexOf(el) > -1
    });
}

console.log(findCommon(arr1, arr2));