text: 
  // each OutputItem represents one output item information 
  // which will be used to render a react component at output class
  // which can be a string (into a react label)
  // or a tuple of data and layout (into a figure of plotlyjs)
  // and type is a string of "print" or "draw" or "tex" or "formulaTex"
  class OutputItem{
      outputType:string;
      text:string;
      data:[];
      layout:{};
      isPrint() {return this.outputType === "print";}
      isDraw() {return this.outputType==="draw"}
      isTex() {return this.outputType === "tex"}
      isFormulaTex() {return this.outputType === "formulaTex"}
      isMarkdown() {return this.outputType === "markdown"}
  }
  
  export default OutputItem;