JavaScript String replace - How do you use matched variables in the replacement string?

Question

How do you use the matched variables in the pattern in the replacement string?

var regexp = new RegExp(\'needle\', \'ig\');
str.replace(regexp, \'

        

Answer 1

The correct way to use backreferences in JavaScript is via $1...$9.

To make your example work:

var regexp = new RegExp(something, 'ig');
var result = str.replace(regexp, '$1');

More information is available here: http://www.regular-expressions.info/javascript.html#replace