JS

Iterators

 function nombreDelIterador() {
  return {
    next: function() {
      return {
        value: "El valor actual del iterador",
        done: false, // true | false
      }
    }
  };
}

// Samuel Burbano
const socials = {
  twitter: "@iosamuel",
  facebook: "iosamuel.dev",
  github: "iosamuel",
  web: "iosamuel.dev"
};

JS

Iterators

 function crearIterador(arreglo) {
  var siguienteIndice = 0;
  
  return {
    next: function() {
        return siguienteIndice < arreglo.length
          ? { value: arreglo[siguienteIndice++], done: false }
          : { done: true };
    }
  }
}
 
const thankYou = crearIterador(['ariana', 'grande']);
console.log(thankYou.next()); // { value: "ariana", done: false }
console.log(thankYou.next()); // { value: "grande", done: false }
console.log(thankYou.next()); // { value: undefined, done: true }

JS

Generators

 function* crearGenerator(arreglo) {
  let index = 0;
 
  while (index < arreglo.length) {
    yield arreglo[index++];
  }
}
 
const thankYou = crearGenerator(['ariana', 'grande']);
console.log(thankYou.next()); // { value: "ariana", done: false }
console.log(thankYou.next()); // { value: "grande", done: false }
console.log(thankYou.next()); // { value: undefined, done: true }

JS

Symbol

Symbol()

!=

 const a = Symbol();
const b = Symbol();
 
console.log(a === b); // false

JS

Symbol

 const a = Symbol();
const b = Symbol();
 
const obj = {};
obj[a] = "a";
obj[b] = "b";
obj.c = "c";
obj.d = "d";
 
for (let i in obj) {
  console.log(i); // solo imprime "c" y "d"
}
 
obj[a]; // "a"

JS

Ejemplo

 class RandomArray extends Array {
  [Symbol.iterator]() {
    let getRange = n => Array.from(new Array(n), (_, i) => i); // [0, n)
    let shuffle = arr => { // Durstenfeld shuffle
      for (let i = arr.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [arr[i], arr[j]] = [arr[j], arr[i]];
      }
      return arr;
    };
 
    let i = 0;
    let indices = shuffle(getRange(this.length));
 
    return {
      next: () => ({
        value: this[indices[i++]],
        done: i > this.length
      })
    }
  }
}

JS Iterators function nombreDelIterador ( ) { return { next : function ( ) { return { value : "El valor actual del iterador" , done : false , // true | false } } }; } // Samuel Burbano const socials = { twitter : "@iosamuel" , facebook : "iosamuel.dev" , github : "iosamuel" , web : "iosamuel.dev" };

Iterators

By Samuel Burbano

Iterators

5 years ago
344

Samuel Burbano

Coding is easy, logically coding is what makes it special.

	const miIterable = [1, 2, 3, 4, 5];
	for (let valor of miIterable) {
	console.log(valor)
	}
	// 1
	// 2
	// 3
	// 4
	// 5

	const thankYou = {
	nombre: "ariana",
	apellido: "grande",
	};

	for (let prop in thankYou) {
	console.log(prop);
	}
	// nombre
	// apellido

	const thankYou = {
	nombre: "ariana",
	apellido: "grande",
	[Symbol.iterator]: function*() {
	yield this.nombre;
	yield this.apellido;
	}
	};

	const arreglo = [...thankYou]; // ["ariana", "grande"]

	for (let valor of thankYou) {
	console.log(valor);
	}
	// ariana
	// grande

	const [ nombre, apellido ] = thankYou;
	console.log(nombre, apellido); // ariana grande

	function nombreDelIterador() {
	return {
	next: function() {
	return {
	value: "El valor actual del iterador",
	done: false, // true \| false
	}
	}
	};
	}

	function crearIterador(arreglo) {
	var siguienteIndice = 0;

	return {
	next: function() {
	return siguienteIndice < arreglo.length
	? { value: arreglo[siguienteIndice++], done: false }
	: { done: true };
	}
	}
	}

	const thankYou = crearIterador(['ariana', 'grande']);
	console.log(thankYou.next()); // { value: "ariana", done: false }
	console.log(thankYou.next()); // { value: "grande", done: false }
	console.log(thankYou.next()); // { value: undefined, done: true }

	function* crearGenerator(arreglo) {
	let index = 0;

	while (index < arreglo.length) {
	yield arreglo[index++];
	}
	}

	const thankYou = crearGenerator(['ariana', 'grande']);
	console.log(thankYou.next()); // { value: "ariana", done: false }
	console.log(thankYou.next()); // { value: "grande", done: false }
	console.log(thankYou.next()); // { value: undefined, done: true }

	const miIterable = "Hola!";
	[...miIterable]
	// ["H", "o", "l", "a", "!"]

	for (let el of thankYou) {
	console.log(el);
	}
	// ERROR: thankYou is not iterable

	const a = Symbol();
	const b = Symbol();

	console.log(a === b); // false

	const a = Symbol();
	const b = Symbol();

	const obj = {};
	obj[a] = "a";
	obj[b] = "b";
	obj.c = "c";
	obj.d = "d";

	for (let i in obj) {
	console.log(i); // solo imprime "c" y "d"
	}

	obj[a]; // "a"

	class RandomArray extends Array {
	[Symbol.iterator]() {
	let getRange = n => Array.from(new Array(n), (_, i) => i); // [0, n)
	let shuffle = arr => { // Durstenfeld shuffle
	for (let i = arr.length - 1; i > 0; i--) {
	const j = Math.floor(Math.random() * (i + 1));
	[arr[i], arr[j]] = [arr[j], arr[i]];
	}
	return arr;
	};

	let i = 0;
	let indices = shuffle(getRange(this.length));

	return {
	next: () => ({
	value: this[indices[i++]],
	done: i > this.length
	})
	}
	}
	}

	let canciones = new RandomArray("7 rings", "Bang Bang", "Thank U, Next", "Side to Side", "break up with your girlfriend, i'm bored", "Into You", "Problem", "god is a woman", "No Tears Left to Cry", "Don’t Call Me Angel", "dangerous woman", "Boyfriend", "One Last Time", "Breathin", "Love Me Harder", "Santa Tell Me", "Almost Is Never Enough", "Focus", "Break Free", "needy");
	console.log([...canciones]);
	console.log([...canciones]);
	console.log([...canciones]);

	for (let cancion of canciones) {
	console.log(cancion); // CANCION RANDOM!
	}

JS

Iterators

Iterators

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