encode-quoted-printable/lib/to-utf8-array.js

Encode a string to a quoted printable format for emails

// Thanks to joni@github https://gist.github.com/joni/3760795
function toUTF8Array(str) {
  var utf8 = [];
  var i;
  var charcode;

  for (i=0; i < str.length; i++) {
    charcode = str.charCodeAt(i);
    if (charcode < 0x80) {
      utf8.push(charcode);
    }
    else if (charcode < 0x800) {
      utf8.push(0xc0 | (charcode >> 6), 0x80 | (charcode & 0x3f));
    }
    else if (charcode < 0xd800 || charcode >= 0xe000) {
      utf8.push(0xe0 | (charcode >> 12), 0x80 | ((charcode>>6) & 0x3f), 0x80 | (charcode & 0x3f));
    }
    // surrogate pair
    else {
      i++;
      // UTF-16 encodes 0x10000-0x10FFFF by
      // subtracting 0x10000 and splitting the
      // 20 bits of 0x0-0xFFFFF into two halves
      charcode = 0x10000 + (((charcode & 0x3ff)<<10) | (str.charCodeAt(i) & 0x3ff));
      utf8.push(0xf0 | (charcode >>18), 0x80 | ((charcode>>12) & 0x3f), 0x80 | ((charcode>>6) & 0x3f), 0x80 | (charcode & 0x3f));
    }
  }

  return utf8;
}

module.exports = toUTF8Array;