I'm aware that the immediate response is going to be to use promises for the following problem. However, I've looked at every example I can and nothing seems to be readable to me. Most is done through HTML examples, which I don't understand. Similar posts here have a plethora of arguments on which syntax is appropriate which furthers the confusion. So, please show me how I might use a promise to do the following or if another solution is better.

I'd like for a function to check if the cache is available, and if not, it will reinitialize the cache:

function valData(){
  if (arrOfNames || arrOfRanges == null){
    initializeGame();
    Logger.log('Game Initialized')
  }
  else {
    Logger.log('Data Available')
  }
};

I'm aware this is likely sloppy, but stay with me

This function works as intended, as does the following:

function reqVal(valname,x){
  if (x == 0){
    var nameArr = convToString(arrOfNames);
    var valIndex = nameArr.indexOf("" + valname)
    return arrOfRanges[valIndex];
  }
  else {
    var nameArr = convToString(arrOfNames);
    var valIndex = nameArr.indexOf("" + valname)
    return valIndex;
  }
};

Again, very very sloppy but Ill clean things up once I can make them function

Both of these scripts work fine on their own and return what I need. But if I have a third script:

function test(){
  valData();
  var valNum = reqVal('curHP', 0);
  var valIndex = reqVal('curHP',1)
  var newNum = valNum - 5;
  Logger.log(valNum)
  Logger.log(newNum)
  Logger.log(valIndex)
};

The reqVal() function fails due to the asynchronous nature of GAS and the Cache having expired, but the valData() function succeeds and produces the needed array. So, I know I need to add a promise in valData() that the reqVal() function can read from but have no idea how to format that as examples I've seen have been very unclear.