How can I replace a regex substring match in Javascript?

Question

var str   = \'asd-0.testing\';
var regex = /asd-(\\d)\\.\\w+/;

str.replace(regex, 1);

That replaces the entire string str with

Answer 1

I think the simplest way to achieve your goal is this:

var str   = 'asd-0.testing';
var regex = /(asd-)(\d)(\.\w+)/;
var anyNumber = 1;
var res = str.replace(regex, `$1${anyNumber}$3`);