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 would get the part before and after what you want to replace and put them either side.

Like:

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

var matches = str.match(regex);

var result = matches[1] + "1" + matches[2];

// With ES6:
var result = `${matches[1]}1${matches[2]}`;