Multiline String; Delete Footer Lines

// GraalJS Script (engine type: 2)
// (c) 2021, Questetra, Inc. (the MIT License)

//////// START "main()" ////////
main();
function main(){ 


//// == Config Retrieving / 工程コンフィグの参照 ==
const dataIdA = configs.get( "conf_DataIdA" ) + ""; // config required
const delNum  = configs.get( "conf_DelNum" )  + ""; // config required
const dataIdC = configs.get( "conf_DataIdC" ) + ""; // config required
const intDelNum  = parseInt( delNum );
// Design-time Config Format Check
if ( isNaN( intDelNum )){
  throw new Error( "\n AutomatedTask UnexpectedConfigError:" +
                   " Config DelNum is not an integer \n" );
}


//// == Data Retrieving / ワークフローデータの参照 ==
// Run-time Data Format Check
if( engine.findDataByNumber( dataIdA ) === null ){
  throw new Error( "\n AutomatedTask UnexpectedStringError:" +
                   " String {A} is null \n" );
}
const inputText = (engine.findDataByNumber( dataIdA ) + "").trim();
if( inputText === "" ){
  throw new Error( "\n AutomatedTask UnexpectedStringError:" +
                   " String {A} is empty \n" );
}


//// == Calculating / 演算 ==
let   outputText = "";
const arrInputText = inputText.split("\n");
engine.log( " AutomatedTask MultilineString:" + 
            " String {A}, number of lines " + arrInputText.length );
if( arrInputText.length < intDelNum ){
  engine.log( " AutomatedTask StringWarning:" +
    " String {A}, number of lines is smaller than DelNum \n" );
}else{
  for (let i = 0; i < arrInputText.length - intDelNum; i++){
    outputText += arrInputText[i];
    if( i !== arrInputText.length - intDelNum - 1 ){
      outputText += "\n";
    }
  }
}


//// == Data Updating / ワークフローデータへの代入 ==
engine.setDataByNumber( dataIdC, outputText );


} //////// END "main()" ////////