how do I find the value stored in array of object and console the key?

Question

I am trying to write a function that takes pokemon's name as an argument and find out which all pokemon have that name in their “next_evolution” field

Consider the following JSON dataset -

visit https://raw.githubusercontent.com/Biuni/PokemonGO-Pokedex/master/pokedex.json

my code for the said question:

var infoOfPokemon = function(nameOfPokemon, allPokemon) {
  for (x in allPokemon) {
    if (allPokemon[x].next_evolution &&
      allPokemon[x].next_evolution.includes(nameOfPokemon)) {
      console.log('pokemons found: ' + allPokemon[x].name)
    } else {
      null
    }
  }
}
var nameOfPokemon = prompt('enter the name of Pokemon')
infoOfPokemon(nameOfPokemon, pokemonData.pokemon)

my function isn't returning the name of pokemon that has its name in next_evolution field.

Answer 1

You should consider using some and filter . That would make things easy for you

pokemonData.pokemon.filter(o=> o.next_evolution.some(e=> e.name === nameOfPokemon))

Answer 2

In your JSON object, next_evolution object is an array of Objects and it not populated always.

You were operating directly on the next_evolution field considering it as String array hence your include didn't work.

Below code is tedious but gives explanation of your wrong iteration

var infoOfPokemon = function(nameOfPokemon, allPokemon) {
    for (index in allPokemon) {
        var nextEvolutionObject=allPokemon[index].next_evolution;
      if (nextEvolutionObject){
          for(evolutionIndex in nextEvolutionObject){
              if(nextEvolutionObject[evolutionIndex].name===nameOfPokemon){
                  console.log("Pokemon found :"+nameOfPokemon);
              }
          }

      }
    }
  }
  var nameOfPokemon = prompt('enter the name of Pokemon');
  infoOfPokemon(nameOfPokemon, pokemonData.pokemon)