code: function getDefault() {
    const type = NodeType.DefaultType;
    const token = tokens[pos];
    const line = token.ln;
    const column = token.col;
    const content = joinValues(pos, token.defaultEnd);
  
    pos = token.defaultEnd + 1;
  
    return newNode(type, content, line, column);
  }
docs: Get node with a `!default` word
  @return {Array} `['default', sc]` where `sc` is optional whitespace