How to String.match() distinct it ${SOME_TEXT} using Regex

Question

I need this string:

var x = \'Hi ${name}! How are you? ${name}, you are old! ${name} share with ${other} how do u ${feel}!\'

I need to know

Answer 1

I need to know using Regex how much distinct ${ANY_THING} exists

x.match(/\$\{[^\}]+\}/g)
 .sort()
 .filter(function(element, index, array) {
     return index == array.indexOf(element);
 }) // this .filter() filters out the duplicates (since JS lacks of built in
    // unique filtering functions
 .length;

The code above would return 3, as that's how many distinct items are in the x string.

JSFiddle: http://jsfiddle.net/cae6P/

PS: It's not possible to do it with regular expression only. You need to filter duplicates using the .filter() solution or some other similar