reduce

const posts = [
  {id: "moi", upVotes: 20},
  {id: "toi", upVotes: 89},
  {id: "lui", upVotes: 1},
  {id: "eux", upVotes: 123},];


let [premier,second] = posts.reduce((acc, cur) => [cur, ...acc].sort((a,b) => b.upVotes - a.upVotes).slice(0,2),[]);

console.log(`Au second tour sont présents : ${premier.id} et ${second.id}`);

Générateur

class Matrix {
  constructor(width, height, element = (x, y) => undefined) {
    this.width = width;
    this.height = height;
    this.content = [];

    for (let y = 0; y < height; y++) {
      for (let x = 0; x < width; x++) {
        this.content[y * width + x] = element(x, y);
      }
    }
  }

  get(x, y) {
    return this.content[y * this.width + x];
  }
  set(x, y, value) {
    this.content[y * this.width + x] = value;
  }

 *[Symbol.iterator]() {
          let i=0;
   
          while (i < this.height*this.width) {
              yield {
                x : i%this.width,
                y : Math.floor(i/this.width),
                value : this.content[i]
              }
              i++;
          }
  }
 
}


const width = 3;
let matrix = new Matrix(width, width, (x, y) => `[${x},${y}]= ${y * width + x}`);
for (let {value,x,y} of matrix) {
  console.log(x,y,value);
}

https://es6console.com/jppky2fw/

0 0 [0,0]= 0
1 0 [1,0]= 1
2 0 [2,0]= 2
0 1 [0,1]= 3
1 1 [1,1]= 4
2 1 [2,1]= 5
0 2 [0,2]= 6
1 2 [1,2]= 7
2 2 [2,2]= 8 

Autre exemple : lien

Game !

Destructuring !

const user = {nom: 'me', age: 54, code: 'secret'};

const old = (function ( para ) {
    return function( {nom} ) {
  return {nom}
}})();

console.log(old(user))

const userSecure = ( ({nom, age}) => ({nom, age}) )(user);

Date