JavaScript equivalent to printf/String.Format

Question

I\'m looking for a good JavaScript equivalent of the C/PHP printf() or for C#/Java programmers, String.Format() (IFormatProvider for .

Answer 1

One very slightly different version, the one I prefer (this one uses {xxx} tokens rather than {0} numbered arguments, this is much more self-documenting and suits localization much better):

String.prototype.format = function(tokens) {
  var formatted = this;
  for (var token in tokens)
    if (tokens.hasOwnProperty(token))
      formatted = formatted.replace(RegExp("{" + token + "}", "g"), tokens[token]);
  return formatted;
};

A variation would be:

  var formatted = l(this);

that calls an l() localization function first.