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

String.Format method from .NET Framework has multiple signatures. The one I like the most uses params keyword in its prototype, i.e.:

public static string Format(
    string format,
    params Object[] args
)

Using this version, you can not only pass variable number of arguments to it but also an array argument.

Because I like the straightforward solution provided by Jeremy, I'd like to extend it a bit:

var StringHelpers = {
    format: function(format, args) {
        var i;
        if (args instanceof Array) {
            for (i = 0; i < args.length; i++) {
                format = format.replace(new RegExp('\\{' + i + '\\}', 'gm'), args[i]);
            }
            return format;
        }
        for (i = 0; i < arguments.length - 1; i++) {
            format = format.replace(new RegExp('\\{' + i + '\\}', 'gm'), arguments[i + 1]);
        }
        return format;
    }
};

Now you can use your JavaScript version of String.Format in the following manners:

StringHelpers.format("{0}{1}", "a", "b")

and

StringHelpers.format("{0}{1}", ["a", "b"])