closure.js

// ==== Closures ==== 

/* Task 1: Study the code below and explain in your own words why nested function can access the variable internal. */


const external = "I'm outside the function";

function myFunction() {
  console.log(external);
  const internal = "Hello! I'm inside myFunction!";

  function nestedFunction() {
    console.log(internal);
  };
  nestedFunction();
}
myFunction();

// Explanation: 

// nestfunctions can acess the variable internal because nested functions, although is a new function, 
//its still in the block scope of myFunction.
//a function that wasnt in the same block scope couldnt access that variable.

/* Task 2: Counter */

/* Create a function called `sumation` that accepts a parameter
 and uses a counter to return the summation of that number
. For example, `summation(4)` should return 10 because 1+2+3+4 is 10. */

function sumation(n) {
  return n * (n + 1) / 2;
}

console.log( sumation(4) );