JSFiddle - React, Tailwind, and code Playground

HTML

<div id="answer"></div>

JavaScript

var string = 'This is a text that needs to change';
var array1 = new Array('a', 'e', 'i', 'o', 'u');
var array2 = new Array('1', '2', '3', '4', '5');

var regex = new RegExp( '['+array1.join('')+']', 'g' );

var lookup = {};
for( var i=0 ; i<array1.length ; ++i )
    lookup[array1[i]] = array2[i];

document.getElementById("answer").innerHTML =
    string.replace(regex, function(c) { return lookup[c]; });