JavaScript Map

A much cleaner and performant alternative to objects.

const myPokemons = new Map();

const bulbasaur = { id: 1, name: "Bulbasaur" };

myPokemons.set(bulbasaur.id, bulbasaur);
myPokemons.delete(bulbasaur.id);

Iterating

for (const [key, value] of myPokemons) {
  // ...
}

• Cleaner to iterate compared to objects.
• Iterates in the order of entry insertion.

Iterators

// Iterator of all map keys
myPokemons.keys();

// Iterator of all map values
myPokemons.values();

Cloning

const clonedPokemons = new Map(myPokemons);

// deep cloning
const deepClone = structuredClone(myPokemons);

Converting to objects

const myObj = Object.fromEntries(myMap);

Converting to Map

const myMap = new Map(Object.entries(myObj));

Use any type of object as keys

myMap.set(document.body, value);
myMap.set(function() {}, value);
myMap.set(myPokemon, value);