JSFiddle - React, Tailwind, and code Playground

JavaScript

var input = "\\test\red\bob\fred\new";

var output = input
    .replace(/[\r]/g, 'r')
    .replace(/[\b]/g, 'b')
    .replace(/[\f]/g, 'f')
    .replace(/[\n]/g, 'n')
    .replace(/\\/g, '');

alert(output);