JavaScript - string regex backreferences

Question

You can backreference like this in JavaScript:

var str = \"123 $test 123\";
str = str.replace(/(\\$)([a-z]+)/gi, \"$2\");

This would (quite

Answer 1

Pass a function as the second argument to replace:

str = str.replace(/(\$)([a-z]+)/gi, myReplace);

function myReplace(str, group1, group2) {
    return "+" + group2 + "+";
}

This capability has been around since Javascript 1.3, according to mozilla.org.