Question

var x = '#google';    // or '@google' or '%google'
var pattern = new RegExp('(^|\\s)' + x);
var result = txt.replace(pattern, '$1' + 'MyNewWord');

this code works fine to replace #google

if I use & or @ instead of # it works fine

only it doesn’t work when I use $ instead of # so the following code doesn’t work properly

var x = '$google';   
var pattern = new RegExp('(^|\\s)' + x);
var result = txt.replace(pattern, '$1' + 'MyNewWord'); 

ps I used new RegEXP because x will be user input.

Answer 1

$ is a special character in a RegExp so you need to escape it:

var x = '\\$google';
var pattern = new RegExp('(^|\\s)' + x);