JSFiddle - React, Tailwind, and code Playground

JavaScript

var array1 = ["50", "51", "52", "53", "54", "55", "56", "57", "58", "59"];
var array2 = ["59", "55", "511", "123"];
var stored_index = array2.map(function (val) {
    return array1.indexOf(val);
});

alert(stored_index)