Functions & Closures

What is a closure in JavaScript?

What does this output?

function makeAdder(x) {
  return function(y) {
    return x + y
  }
}
const add5 = makeAdder(5)
console.log(add5(3))

What is printed?

function outer() {
  let count = 0
  return function() {
    count++
    return count
  }
}
const inc = outer()
console.log(inc())
console.log(inc())
console.log(inc())