simple_sprintf.js

/*
 * %s, %d, %f only
 */
const _SPRINTF_HASH = {
    '%s': String,
    '%d': parseInt,
    '%f': parseFloat,
};

var sprintf = function (str) {
    let args = Array.slice(arguments, 1);
    return str.replace(/%[sdf]/g, function(m) _SPRINTF_HASH[m](args.shift()));
};