How can I check if all variables are different?

Question

Is it possible to check if all variables are different from each other in another way than this?

var a = 1, b = 2, c = 3, d = 4;

if(a != b && a != c && a != d && b != a && b != c && b != d && c != a && c != b && c != d && d != a && d != b && d != c){
  //All numbers are different
}

for example

if(a != b != c != d){

}

Answer 1

You can store them all in an object and check if the number of keys is equal to the number of variables used, like this

var dummy = {};
dummy[a] = true;
dummy[b] = true;
dummy[c] = true;
dummy[d] = true;
console.log(Object.keys(dummy).length === 4);

If the values are different, then a new key will be created every time and the number of keys will be equal to the number of variables used.