Find Last Occurrence of Regex Word

You can use negative lookahead to get the last match:

/(\btotal\b)(?!.*\b\1\b)/

RegEx Demo 1

RegEx Demo 2

(?!.*\1) is negative lookahead to assert that captured group #1 i.e. total word is NOT present ahead of the present match.

Without using the lookaheads but using the same regex (having applied the g, i.e. global, flag), the option would be to match the string with regex and get the last match.

var matches = yourString.match(/\btotal\b/g);
var lastMatch = matches[matches.length-1];