“或”条件不起作用JavaScript

Question

I have a condition which should predict run the function. but it wouldn't work.

if ((event.keyCode !== 40) || (event.keyCode !== 38)) {
        self.inputVal = input.value;
        var result = pokemonNames.filter(function(pokemon) {
          return pokemon.includes(self.inputVal.toLowerCase());
        });
        if (result.length > 5) {
          result = result.filter(function(pokemon, index) {
            return index < 5;
          });
        }

when I use just event.keyCode !== 40 it works fine, but when I use (event.keyCode !== 40) || (event.keyCode !== 38) (event.keyCode !== 40) || (event.keyCode !== 38) it would work.

Answer 1

If you want to execute the if block if the event.keyCode is NOT 40 or 38 you want this

((event.keyCode !== 40) && (event.keyCode !== 38))

If you want to execute the code if event.keyCode is 40 or 38

((event.keyCode == 40) || (event.keyCode == 38))

Answer 2

As Aaron pointed out in the comments, it will always resolve as true . If the number is 40, the second condition will be true (since it's not 38), and vice versa. Use && instead and it will work.