JavaScript function to format strings with the format {#}

string-format.js

var Format = (function () {
    "use strict";
 
    var refToString, toString, re, slice, ret;
 
    refToString = {}.toString;
    toString = function (p) {
        return refToString.call(p);
    };
    re = /\{(\d+)\}/g;
    slice = function (args, start) {
        var arr, i, j, cur;
        start = start || 0;
        arr = [];
        for (i = start, j = args.length; i < j; i++) {
            cur = args[i];
            arr.push(cur);
        }
        return arr;
    };
    ret = function (str, args) {
        if (toString(args) !== "[object Object]") {
            args = slice(arguments, 1);
        }
        return str.replace(re, function (match, $1) {
            var arg = args[$1];
            return arg === undefined ? match : arg;
        });
    };

    return ret;
}());