index.js

const outerFunc = () => {
  console.log("Outer Function")
  const innerFunc = () =>{
    console.log("Inner Function")
  }
  return innerFunc
}

outerFunc()()
// OUTPUT
// Outer Function
// Inner Function

const myFunc = outerFunc()
myFunc()
myFunc()
// OUTPUT
// Outer Function
// Inner Function
// Inner Function