sprintf.js

// Author: Allex Wang
// GistID: ebdb822006afb8b1c2df
// GistURL: https://gist.github.com/ebdb822006afb8b1c2df

// Simple sprintf implement
var sprintf = function(format) {
    var return_str = new String(format);
    var match;
    var reg = /%([osif])/i;
    var before, after, replacement;
    var argIndex = 1;
    do {
        match = reg.exec(return_str);
        if (match) {
            before = return_str.substr(0, match.index);
            after = return_str.substr(match.index + match[0].length, return_str.length);
            replacement = '';
            switch (match[1]) {
                case 'o':
                    if (typeof JSON === 'object' && JSON && JSON.stringify) {
                        replacement = JSON.stringify(arguments[argIndex]);
                    } else {
                        replacement = arguments[argIndex].toString();
                    }
                    break;
                case 'i':
                    replacement = parseInt(arguments[argIndex]).toString()
                    break;
                case 'f':
                    replacement = arguments[argIndex].toFixed(3)
                    break;
                case 's':
                    replacement = String(arguments[argIndex])
            }
            return_str = before + replacement + after;
            argIndex++;
        }
    } while (match);
    return return_str;
};

console.log(sprintf('Hi, %s, count: %f, data: %o', 'Allex', 1.2222444, {json:1}));