lib/parse.js
function parseSymbol () {
  if (tokenType === TOKENTYPE.SYMBOL) {
    if (token === 'true') {
      getToken();
      return true;
    }
    if (token === 'false') {
      getToken();
      return false;
    }
    if (token === 'null') {
      getToken();
      return null;
    }

    throw createSyntaxError('Unknown symbol "' + token + '"');
  }

  return parseEnd();
}
function parseSymbol () {
  if (tokenType === TOKENTYPE.SYMBOL) {
    if (token === 'true') {
      getToken();
      return true;
    }
    if (token === 'false') {
      getToken();
      return false;
    }
    if (token === 'null') {
      getToken();
      return null;
    }

    throw createSyntaxError('Unknown symbol "' + token + '"');
  }

  return parseEnd();
}
function parseSymbol ( ) { if ( tokenType === TOKENTYPE . SYMBOL ) { if ( token === 'true' ) { getToken ( ) ; return true ; } if ( token === 'false' ) { getToken ( ) ; return false ; } if ( token === 'null' ) { getToken ( ) ; return null ; } throw createSyntaxError ( 'Unknown symbol "' + token + '"' ) ; } return parseEnd ( ) ; }
Parse constants true, false, null
@return {boolean | null}
Parse constants true false null