hyper/lib/utils/key-code.js

/**
 * Keyboard event keyCodes have proven to be really unreliable.
 * This util function will cover most of the edge cases where
 * String.fromCharCode() doesn't work.
 */

const _toAscii = {
  '188': '44',
  '109': '45',
  '190': '46',
  '191': '47',
  '192': '96',
  '220': '92',
  '222': '39',
  '221': '93',
  '219': '91',
  '173': '45',
  '187': '61', // IE Key codes
  '186': '59', // IE Key codes
  '189': '45'  // IE Key codes
};

const _shiftUps = {
  '96': '~',
  '49': '!',
  '50': '@',
  '51': '#',
  '52': '$',
  '53': '%',
  '54': '^',
  '55': '&',
  '56': '*',
  '57': '(',
  '48': ')',
  '45': '_',
  '61': '+',
  '91': '{',
  '93': '}',
  '92': '|',
  '59': ':',
  '39': '\'',
  '44': '<',
  '46': '>',
  '47': '?'
};

const _arrowKeys = {
  '38': '',
  '40': '',
  '39': '',
  '37': ''
};

/**
 * This fn takes a keyboard event and returns
 * the character that was pressed. This fn
 * purposely doesn't take into account if the alt/meta
 * key was pressed.
 */
export default function fromCharCode(e) {
  let code = String(e.which);

  if ({}.hasOwnProperty.call(_arrowKeys, code)) {
    return _arrowKeys[code];
  }

  if ({}.hasOwnProperty.call(_toAscii, code)) {
    code = _toAscii[code];
  }

  const char = String.fromCharCode(code);
  if (e.shiftKey) {
    if ({}.hasOwnProperty.call(_shiftUps, code)) {
      return _shiftUps[code];
    }
    return char.toUpperCase();
  }
  return char.toLowerCase();
}