Use of String.Format in JavaScript?

Question

This is driving me nuts. I believe I asked this exact same question, but I can\'t find it any more (I used Stack Overflow search, Google Search, manually searched my po

Answer 1

Aside from the fact that you are modifying the String prototype, there is nothing wrong with the function you provided. The way you would use it is this way:

"Hello {0},".format(["Bob"]);

If you wanted it as a stand-alone function, you could alter it slightly to this:

function format(string, object) {
    return string.replace(/{([^{}]*)}/g,
       function(match, group_match)
       {
           var data = object[group_match];
           return typeof data === 'string' ? data : match;
       }
    );
}

Vittore's method is also good; his function is called with each additional formating option being passed in as an argument, while yours expects an object.

What this actually looks like is John Resig's micro-templating engine.