setbeginnerconst m = new Map()
m.set('a', 1)
m.set('b', 2)
console.log(m.size) // β 2Use Map.set() to add or update a key-value pair; it returns the map itself.
set() adds or updates a key-value pair and returns the Map itself, enabling chaining.
Challenge: Verify that map.set('a', 1) returns the same map instance.