JavaScript if alternative when checking for the same thing multiple times

Question

So I'm trying to check for an undefined object out of multiple ones and then do something with that specific one. This code below works but I can imagine that there's a better way than just using else if 20 times in a row.

   if (duelswins === undefined) {
      document.getElementById('duels_wins').style.display = 'none'
   } else if (duelslosses === undefined) {
      document.getElementById('duels_losses').style.display = 'none'
   } else if (duelskills === undefined) {
      document.getElementById('duels_kills').style.display = 'none'
   } else if (duelsdeaths === undefined) {
     document.getElementById('duels_deaths').style.display = 'none'
   } else if (duelsgoals === undefined) {
     document.getElementById('duels_goals').style.display = 'none'
   } else if (duelskdr === undefined) {
     document.getElementById('duels_kdr').style.display = 'none'
   } else if (duelswlr === undefined) {
     document.getElementById('duels_wlr').style.display = 'none'
   } else if (duelsgwr === undefined) {
     document.getElementById('duels_gwr').style.display = 'none'
   }

There can be multiple ones of those being undefined but it could also be also none of them.

This is just an example, I'm mostly interested if there's and alternative for using so many if statements just for checking basically the same thing over and over again.

user_1967864 · Answer

Instead of using individual variables you can put these values into an object and then loop over the keys/values. I'm not sure what your requirements are exactly but this might be a step in the right direction:

const data = {
  duels_wins: undefined,
  duels_losses: 123,
  duels_deaths: undefined,
  // ...
};

Object.entries(data).forEach(([key, value]) => {
  if (value === undefined) {
    document.getElementById(key).style.display = 'none';
  }
});

duels_wins
duels_losses
duels_deaths

JavaScript if alternative when checking for the same thing multiple times

1 Answers