Why filter function is returning array even when it does not pass the condition

Achint vishwas 0
Viewed 35

I'm struggling to understand why this code is not working. its working with a small dataset though.

const gl = wList.GreateLeague
const data = JSON.parse(fs.readFileSync("./raw/data.json"))
    
(function () {
  let glFinds = data.pokemons.filter((poke) => gl.hasOwnProperty(poke.pokemon_id))
  let ax = glFinds.filter((p) => {
    return gl[p.pokemon_id].stats.filter((ammo) => {
      return (
        p.attack === ammo[0] && p.defence === ammo[1] && p.stamina === ammo[2]
      );
    });
  });
  console.log(glFinds)
  console.log(ax)
})();

my output for both console is same, therefore filter on ax is not working. ax is working fine if I include testData.json which is a smaller then data.json.

edit: stats look like this. here [0],[1],[2] are the attack defense and stamina

"stats": [
          [1, 15, 15, 20.5, 1494],
          [0, 13, 11, 20.5, 1494],
          [2, 14, 15, 20.5, 1494],
          [0, 10, 15, 20.5, 1494],
          [1, 12, 11, 20.5, 1494],
          [0, 15, 15, 20.5, 1494],
          [3, 13, 15, 20.5, 1494],
          [0, 14, 10, 20.5, 1494],
          [2, 15, 14, 20.5, 1494],
          [0, 11, 13, 20.5, 1494]
        ],

my data files have array of objects like this:

{
      "pokemon_id": 155,
      "attack": 2,
      "defence": 5,
      "stamina": 0,
      "move1": 209,
      "move2": 125,
      "level": 4,
    }

I am trying to filter any object that matches (0,1,2 index) of stats array, object's attack, defense and stamina must match any of the stats array first 3 element.

json arrays node.js javascript
1 Answers

The function inside filter must return true or false, depending on whether the current item shall be included in the output array or not. But your function returns gl[p.pokemon_id].stats.filter(...), which is an array, as Andreas already pointed out.

When trying to evaluate an array as true or false, it counts as true (even if it is empty), therefore your whole filter procedure effectively does nothing.

if ([]) console.log(true);
// true
Heiko Theißen0
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