Exemples
const cours = { html: 12, css: 2, JS: 30 };
Object.entries(cours)
> Array [Array ["html", 12], Array ["css", 2], Array ["JS", 30]]
Object.fromEntries(Object.entries(cours))
> Object { html: 12, css: 2, JS: 30 }
En action
const cours = { html: 12, css: 2, JS: 30 };
const  choix = Object.fromEntries(
  Object.entries(cours)
  .filter(([ _, val ]) => val>10 )
);
console.log(choix); // > Object { html: 12, JS: 30 }
En action
const words = ["Beau", "cool", "Ange",
"Ananas", "ballon"];
const alpha = words.reduce((a, x) => {
const l = x[0].toUpperCase()
if(!a[l]) a[l] = [];
a[l].push(x);
return a; }, {});
const  glosaire = Object.fromEntries(
  Object.entries(alpha)
  .sort(([a] , [b]) => a<b?-1:1));
console.log(glosaire); //
- [object Object] {
 A: ["Ange", "Ananas"],
 B: ["Beau", "ballon"],
 C: ["cool"]
 }