sprintf equivalent for client-side JavaScript

Question

I know that console.log supports at least some of the basic features of printf from C through messing around, but I was curious of a way to take advantage of console.log's implementation to create something similar to sprintf. I know you can't simply use .bind or .apply since console.log doesn't actually return the string, so is there a way around this?

If this isn't actually possible, is there some other little-known native implementation that's only a few lines of code away from achieving sprintf in JavaScript?

For those who do not know what sprintf is exactly, here is some documentation from tutorialspoint. Example usage I'm looking for is below:

var string1 = sprintf("Hello, %s!", "world");
var string2 = sprintf("The answer to everything is %d.", 42);

Answer 1

Keep it simple

var sprintf = (str, ...argv) => !argv.length ? str : 
    sprintf(str = str.replace(sprintf.token||"$", argv.shift()), ...argv);

Since Javascript handles data types automatically, there is no need for type options.

If you need padding, "15".padStart(5,"0") = ("00000"+15).slice(-5) = "00015".

Usage

var sprintf = (str, ...argv) => !argv.length ? str : 
    sprintf(str = str.replace(sprintf.token||"$", argv.shift()), ...argv);

alert(sprintf("Success after $ clicks ($ seconds).", 15, 4.569));
sprintf.token = "_";
alert(sprintf("Failure after _ clicks (_ seconds).", 5, 1.569));

sprintf.token = "%";
var a = "%<br>%<br>%";
var b = sprintf("% plus % is %", 0, 1, 0 + 1);
var c = sprintf("Hello, %!", "world");
var d = sprintf("The answer to everything is %.", 42);
document.write(sprintf(a,b,c,d));

Answer 2

Try utilizing eval , .replace

var sprintf = function sprintf() {
  // arguments
  var args = Array.prototype.slice.call(arguments)
    // parameters for string
  , n = args.slice(1, -1)
    // string
  , text = args[0]
    // check for `Number`
  , _res = isNaN(parseInt(args[args.length - 1])) 
             ? args[args.length - 1] 
               // alternatively, if string passed
               // as last argument to `sprintf`,
               // `eval(args[args.length - 1])`
             : Number(args[args.length - 1]) 
    // array of replacement values
  , arr = n.concat(_res)
    // `res`: `text`
  , res = text;
  // loop `arr` items
  for (var i = 0; i < arr.length; i++) {
    // replace formatted characters within `res` with `arr` at index `i`
    res = res.replace(/%d|%s/, arr[i])
  }
  // return string `res`
  return res
};

document.write(sprintf("%d plus %d is %d", 0, 1, 0 + 1) 
               + "<br>" 
               + sprintf("Hello, %s!", "world") 
               + "<br>" 
               + sprintf("The answer to everything is %d.", 42)
              );