? in map in javascript code example

Example 1: map in js

//map() methods returns a new array
const data = {name: "laptop", brands: ["dell", "acer", "asus"]}
let inside_data = data.brands.map((i) => {
	console.log(i); //dell acer asus
});

Example 2: functions in map javascript

const map = new Map();

function foo() {
 return "Hello World!"; 
}

map.set("foo", foo);

console.log(map.get("foo")()); // Output: "Hello World!