Why does String.match( / \d*/ ) return an empty string?

Question

Can someone help me to understand why using \\d* returns an array containing an empty string, whereas using \\d+ returns [\"100\"] (as expected). I get why the \\d+ works, b

Answer 1

* means 0 or more, so it's matching 0 times. You need to use + for 1 or more. By default it's greedy, so will match 100:

var str = 'one to 100';
var regex = /\d+/;
console.log(str.match(regex));
// ["100"]