smartQuotes.js

// replace dumb quotes like "these" with “these”
function smartQuotes(str) {
  return str
    .replace(/'''/g, '\u2034')                                           // triple prime
    .replace(/(\W|^)"(\S)/g, '$1\u201c$2')                               // beginning "
    .replace(/(\u201c[^"]*)"([^"]*$|[^\u201c"]*\u201c)/g, '$1\u201d$2')  // ending "
    .replace(/([^0-9])"/g,'$1\u201d')                                    // remaining " at end of word
    .replace(/''/g, '\u2033')                                            // double prime
    .replace(/(\W|^)'(\S)/g, '$1\u2018$2')                               // beginning '
    .replace(/([a-z])'([a-z])/ig, '$1\u2019$2')                          // conjunction's possession
    .replace(/((\u2018[^']*)|[a-z])'([^0-9]|$)/ig, '$1\u2019$3')         // ending '
    // backwards apostrophe
    .replace(/(\B|^)\u2018(?=([^\u2019]*\u2019\b)*([^\u2019\u2018]*\W[\u2019\u2018]\b|[^\u2019\u2018]*$))/ig, '$1\u2019')
    // abbrev. years like '93
    .replace(/(\u2018)([0-9]{2}[^\u2019]*)(\u2018([^0-9]|$)|$|\u2019[a-z])/ig, '\u2019$2$3')
    .replace(/'/g, '\u2032');
}