JSFiddle - React, Tailwind, and code Playground

JavaScript

var r = /\d+/;
var str = "When I was 10 year old";
var x = $.trim(str.match(r).toString());
var str_split = str.split(x);
var arr = [];
$.each(str_split, function (i, val) {
    arr.push($.trim(val));
    arr.push(x.toString());
});
arr.pop();
console.log(arr);