How to instantiate objects using literal object syntax?

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I have a question maybe a little stupid, but come on, in Javascript, I can create an instance of an object declaring like this, let’s go in an example of a game, where I have to instate bullets to shoot the enemy:

var Bala = {
      myFunctionInit: function myFunctionInit(){
          console.log("Pul!");
      },
      x = 0,
      y = 0,
      speed = 0
};

but then I want to be able to instantiate several of those bullets, but I can’t do something like:

var outraBala = new Bala;

and I understand why I can’t, because the Bullet is already an instantiative object, that I could see giving a "console.log(Bullet);", the question is, how can I instantiate the Bullet, correctly declaring objects in this way?

I know what I can do:

var outraBala = Object.assign({}, Bala);

I also thought about putting the literal object Bala as a return of a function, and so be able to instantiate it like this:

var Bala = function(x, y, speed) {
      return = {
          myFunctionInit: function myFunctionInit(){
              console.log("Pul!");
          },
          x: x,
          y: y,
          speed: speed
       };
}
var outraBala = Bala(1, 1, 10);

but I’m not sure if it’s the best way to deal with this situation.

BS: I don’t want to instantiate objects using class, that way I know how to do it, I want to be able to create them in this declarative way (which I personally think is the clearest of all) and instate them in the best way possible, and if it is my stupidity, I need to understand why.

javascript objects

  • You want to instantiate an object several times, it would not be the case of a constructor function?

  • @Guilhermecostamilam like the one I made(var Bala = function(x, y, speed) {...)?

  • With some corrections, the function you made receives 3 parameters but does not use them instead of = is : inside the returned object

  • @Guilhermecostamilam corrected there, I even traveled with the "=" and forgot to assign the parameters XD

1 answer

1


Like you said you don’t want to use class javascript will have to do a constructor function, to instantiate has some options:

Use the operator new:

function Bala(x, y, speed) {
  this.x = x;
  this.y = y;
  this.speed = speed;
}

let bala1 = new Bala(0, 0, 10);
let bala2 = new Bala(5, 5, 20);
let bala3 = new Bala(3, 0, 1);

console.log(bala1, bala2, bala3);

Directly return the object (I believe this is what you want):

function Bala(x, y, speed) {
  return {
    x: x,
    y: y,
    speed: speed
  };
}

let bala1 = Bala(0, 0, 10);
let bala2 = Bala(5, 5, 20);
let bala3 = Bala(3, 0, 1);

console.log(bala1, bala2, bala3);

They’re both going to be the same, since, under the table, the operator new picks up the this the construction function, that is, the first example is equivalent to:

function Bala(x, y, speed) {
  let object = {};
  object.x = x;
  object.y = y;
  object.speed = speed;

  return object;
}

let bala1 = Bala(0, 0, 10);
let bala2 = Bala(5, 5, 20);
let bala3 = Bala(3, 0, 1);

console.log(bala1, bala2, bala3);

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