mapa dentro de um mapa JavaScript

const map = new Map([1, "a"], [2, "b"], [3, "c"])
const mappedMap = new Map(Array.from(map)
	.map(([key, value]) => { 
  		return [key, value + "d"]
  	})
)
// Map(3) {1 => 'ad', 2 => 'bd', 3 => 'cd'}
NeuroticVegan