How to insert the string in the next empty cell when found no match (GAS)?

Question

I modified the code given by @Alan Wells in Find position of a cell containing a specific string but I don't know why it still inserts the matched string into the next empty cell. It supposed to only insert IF no match found in the entire data range declared in values array. Please help to modify my code below. Thanks.

function findValueInRange () {
  var ss=SpreadsheetApp.openById('THE_SHEET_ID').getSheetByName('staff'),
      theLastColumn = ss.getLastColumn(),
      theLastRow = ss.getLastRow(),
      lastrow=theLastRow,
      name='Dahlia';
  var values = ss.getRange(1,1,theLastRow,theLastColumn).getValues();

  var i=0,rownum=0,thisRow,colvalue,whatToFind = name,j=0;

  for(i=0;i<values.length;i++) {
    thisRow = values[i];
    for (j=1;j<thisRow.length;j++) {
      colvalue = thisRow[j];
      switch(colvalue){
        case whatToFind :Logger.log("The string is in row: "+(i+1)+" and column: "+(j+1));break;
        case '' : Logger.log("just blank");break;
        default : // when no found match
           var lrow=NextCellRng(theLastColumn);//a custom fn to get the last non-blank row number of the last column only
           ss.getRange(lrow,theLastColumn-1).setValue(name); //insert name in the next cell range
           ss.getRange(lrow,theLastColumn).setValue('attended'); // insert status next to the name
           break;
      }
    }
  }
}

Here is the spreadsheet that I need to refer to lookup for the string:-

This spreadsheet stores 2 columns of data which are the name and status 'attended'. I want to utilise the spreadsheet spaces to it's max limit of rows and columns, so once it reaches the max row of first column, it supposed to continue in the next column and so forth. So, the data and search range would grow with the new inserted data when not found. It should be able to grow until the max row and max col that a sheet could handle. In this question, we assume that the max row (5 rows) is reached and that's why the next column is filled and so forth. Whenever a name is entered in a googleform, my custom function should be able to do a validation first:-

1. getValue from the response sheet (in this question, 'Dahlia' is for sampling test)
2. search for the name in the lookup sheet. If exist, return the col & row number & out of loop. But if not, insert the name in the next blank cell and out of loop

But what i noticed is, regardless the name exist or not, the name is still will be inserted. And worse, I realized is the insert process is an infinite loop for that same last column. I had to terminate it at the Project trigger dashboard when I advertently clicked "dismiss" on the script earlier.
When name 'Dahlia' is not found the updated sheet should look like below:-

Answer 1

The break expression within the switch statement only breaks out of the switch, not of the for loops

Thus, even after successfuly finding a name (in one cell), the function will keep looping through the other cells and insert the name in all cells where it is not contained.

• What you need to do is to introduce a global boolean that reflects the status of finding the name
• Once the name is found - set the boolean to true
• Check at the end of each inner loop iteration either the boolean is true
• Once it's true (the name has been found) - break out of the for loops
• After the exiting the for loops without finding the value - go ahead with inserting the value
• The code block setting the value will not be run, if the value has been found in the sheet, and thus the function has been exited before finishing the full iteration

Sample:

  var found = false;
  for(i=0;i<values.length;i++) {
    thisRow = values[i];
    for (j=0;j<thisRow.length;j++) {
      colvalue = thisRow[j];
      Logger.log(colvalue);
      switch(colvalue){
        case whatToFind :
          Logger.log("The string is in row: "+(i+1)+" and column: "+(j+1));
          found = true;
          break;
        case '' : 
          Logger.log("just blank");
          break;
        default : // when no found match
          Logger.log("default");
          break;
      }
      if(found==true){
        break;
      }
    }
  }
  var lrow=NextCellRng(theLastColumn);//a custom fn to get the last non-blank row number of the last column only
  ss.getRange(lrow,theLastColumn-1).setValue(name); //insert name in the next cell range
  ss.getRange(lrow,theLastColumn).setValue('attended'); // insert status next to the name

Answer 2

Thanks a lot to @ziganotschka because his answer has somehow given me some realization on how to really exit the function when search string has been found and insert as new data if not found. We need to use the return command, just that must be placed at the right line of code. So, here's my modified code and answer to what I needed :-

function findValueInRange () {
  var ss=SpreadsheetApp.openById('THIS_SHEET_ID').getSheetByName('staff'),
      theLastColumn = ss.getLastColumn(),
      theLastRow = ss.getLastRow(),
      lastrow=theLastRow,
      name='Dahlia';
  var values = ss.getRange(1,1,theLastRow,theLastColumn).getValues();
  var i=0,rownum=0,thisRow,colvalue,whatToFind = name,j=0;
  
  for(i=0;i<values.length;i++) {
    thisRow = values[i];
    for (j=0;j<thisRow.length;j++) {
    //for (j=1;j<=lastrow;j++) {
      colvalue = thisRow[j];
      switch(colvalue){
        case whatToFind :Logger.log("The string is in row: "+(i+1)+" and column: "+(j+1));return;
        case '' : Logger.log("just blank");break;
        default : Logger.log("default"); break;// when no found match
      }
    }
  }
  var lrow=NextCellRng(theLastColumn);//a custom fn to get the last non-blank row number of the last column only
  ss.getRange(lrow,theLastColumn-1).setValue(name); //insert name in the next cell range
  ss.getRange(lrow,theLastColumn).setValue('attended'); // insert status next to the name 
}