A very simple quote and dash smartener in JS. Used to make my tweets look nicer.

smarten.js

// Change straight quotes to curly and double hyphens to em-dashes.
function smarten(a) {
  a = a.replace(/(^|[-\u2014/(\[{"\s])'/g, "$1\u2018");      // opening singles
  a = a.replace(/'/g, "\u2019");                             // closing singles & apostrophes
  a = a.replace(/(^|[-\u2014/(\[{\u2018\s])"/g, "$1\u201c"); // opening doubles
  a = a.replace(/"/g, "\u201d");                             // closing doubles
  a = a.replace(/--/g, "\u2014");                            // em-dashes
  return a
};