google.script.run.withSuccessHandler don’t return value

it is getting me crazy, the code was working yesterday, but not anymore. I tried to check all syntax again, but the issue still persists. this server-side request from google sheets, shows value on server side (Logger.log()), but returns null in client side! Can you help me to find the issue, please!

  function supervisorLine(lineData){
    if (lineData== 'Name Value is not VALID!' ) {
      console.log("Supervisor Name Issue!");
    } else {
      document.getElementById('Team').value= lineData[7];
      document.getElementById('Shift').value= lineData[12];
      document.getElementById('action').classList.remove("disabled");
      console.log("team "+lineData[7]+" shift "+lineData[12]);
      ////////////////////////////////// need to be Moved somewhere after password check !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
      google.script.run.withSuccessHandler(function(quickStat2){console.log(quickStat2)}).loginRecords(lineData[7],lineData[12]);                
    }
  }  

this is my server side code as well.

function loginRecords(team,shift){
  var sh = ss.getSheetByName("Attn Rec");
  var result= [];
  var matchRec= sh.getRange("a2:l"+sh.getLastRow()).getValues().filter(function(a){
    return a[1]===shift && a[4].valueOf()==team.valueOf()});
  uniqeLogin = removeDups(matchRec.map(function (a){return a[9]}));
  // Logger.log(uniqeLogin);
  uniqeLogin.forEach(function (a){
    var ary=[team,0 ,shift,"",0,0,0,0,0];
    matchRec.forEach(function (r){
      if(r[9]===a) {
        ary[1]= new Date(r[0]);
        ary[3]= r[8];
        switch (r[3].toString().toLowerCase()) {
          case "off-site work":
          case "hr action":
            ary[8]++;
            break;
          case "present":
          case "late transfer":
          case "transfer":
            ary[4]++;
            break;
          case "no show":
            ary[5]++;
            break;
          case "Sick":
          case "vacation":
            ary[7]++;
            break;
          case "late":
          case "approved delay start":
            ary[6]++;
            break;
          }
        }
      });
    result.push(ary);
  });
  Logger.log(result); 
  return result;
}  

for recap, Logger.log(result) returns the array I needed, but console.log(quickStat2) returns null!

Thanks in advance.
M

Answer

I bumped into this issue some time ago and it also nearly drove me mad (oh, the joys of loosely-typed JS!). The problem is that you are trying to return an unacceptable type of data to client-side. Functions called via google.script.run have restrictions on what they can return (for example, you should avoid Date instances).

Restricted types

Currently, you can’t return (take a look at the documentation for detailed explanation of restrictions):

1. Date instances;
2. Function;
3. DOM elements (though form is permitted);

Solution

Changing ary[1]= new Date(r[0]); to ary[1] = r[0]; should do the trick, simply move Date parsing to the client.