How can I filter an array based on its value

Question

I'm creating a catalog of Kingdom Hearts characters and I have a question about how I can filter them

First I created construction classes to make the characters and games

class character {
    constructor(name, gender, alive,  race, description,debut, seriesAppearance) {
        this.name = name;
        this.gender = gender;
        this.alive = alive;
        this.description = description;
        this.race = race
        this.debut = debut;
        this.seriesAppearance = seriesAppearance;
    }
}

class serie {
    constructor(name, year, chronology) {
        this.name = name;
        this.year = year;
        this.chronology = chronology;
    }
}

Then I created the characters and the games themselves

let kh1 = new serie('Kingdom Hearts', '2002', '1')
let khcom = new serie('Kingdom Hearts: Chains of Memories', '2004', '2')
let kh2 = new serie('Kingdom Hearts 2', '2005', '3')

let sora = new character('Sora', 'Male', true, 'Human', 'The Keyblade Master and the protagonist', kh1.name, `${kh1.name}, ${khcom.name} and ${kh2.name}`)
let kairi = new character('Kairi', 'Female', true, 'Human', 'Sora and Riku lost friend', kh1.name, `${kh1.name} and ${kh2.name}`)
let riku = new character('Riku', 'Male', true, 'Human', 'Sasuke of Kingdom Hearts', kh1.name, `${kh1.name} and ${khcom.name}`)
let larxene = new character('Larxene', 'Female', true, 'Nobody', 'Blonde girl who has electrical powers', khcom.name, `${khcom.name} and ${kh2.name}`) 
let axel = new character('Axel', 'Male', true, 'Nobody', 'Man with red hair with fire powers', khcom.name, `${khcom.name} and ${kh2.name}`)
let marluxia = new character('Marluxia', 'Male', true, 'Nobody', 'Pink haired man with a scrythe', khcom.name, khcom.name)
let lexaeus = new character('Lexaeus', 'Male', true, 'Nobody', 'Strong guy who has powers to control the land', khcom.name, `${khcom.name} and ${kh2.name}`)
let vexen = new character('Vexen', 'Male', false, 'Nobody', 'Scientist who created the Riku´s replica', khcom.name, khcom.name)
let replicaRiku = new character('Riku Replica', 'Male', true, 'Replica of the riku that only thinks about protecting Namine', khcom.name, khcom.name)
let namine = new character('Namine', 'Female', true, 'Human', ' Blonde girl who controls people´s memories', khcom.name, khcom.name)
let ansem = new character('Ansem', 'Male', true, 'Nobody', 'Enemy who controlled riku´s mind', kh1.name, kh1.name)

Then I created arrays to organize each type of character and a general array with all

let series = [kh1, kh2, khcom]

let heroes = [sora, kairi, namine]
let enemies = [larxene, axel, marluxia, lexaeus, vexen, replicaRiku, ansem]
let ambiguous = [riku]

let characters = [heroes, enemies, ambiguous]

Now I would like to create a filter that could return all the names of living characters, or human, or male, so I created this test function only with humans that didn't work

  function human(race) {
      if (this.race == 'Human') {
        return this.name
      }
  }

var humans = heroes.filter(human);

how can I make this function work?

Update

this method works for simple arrays

function human(hero) {
    return hero.race === 'Human';
}

const humanNames = heroes.filter(human).map(human => human.name);

How can I make it work on the characters array (an array of arrays)?

Instead of creating lots of variables, consider objects with properties. This makes it a lot easier to organize and manipulate your data. — ggorlen
– ggorlen, Commented May 9, 2020 at 1:37

Robo Robok · Accepted Answer · 2020-05-09 01:23:24Z

3

Array.prototype.filter passes an item to the callback and leaves only those elements that return truthy value. You are looking for the following callback function:

function human(hero) {
    return hero.race === 'Human';
}

If you're interested in names only, you can map your heroes to an array of names:

const humanNames = heroes.filter(human).map(human => human.name);

answered May 9, 2020 at 1:23

Robo Robok

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5 Comments

Rodrigo Liva Over a year ago

this works on single arrays, but if I put the characters which is an array of arrays it doesn't return anything

Robo Robok Over a year ago

Of course. If you have an array of arrays, you work with different data structure and need another solution to your needs.

Rodrigo Liva Over a year ago

which would it be?

Robo Robok Over a year ago

Can you include your case in the question? Also, are you still interested in flat array of heroes or not?

Robo Robok Over a year ago

So, do you really have an array of arrays? Or perhaps that't an object with arrays as values?

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