Why is const declared twice?

Question

const realNumberArray = [4, 5.6, -9.8, 3.14, 42, 6, 8.34];  const squareList = (arr) => {
  "use strict";
  const squaredIntegers = arr.filter( (num) => num > 0 && num % parseInt(num) === 0 ).map( (num) => Math.pow(num, 2) );
  return squaredIntegers;
};

const squaredIntegers = squareList(realNumberArray); 
console.log(squaredIntegers);

Answer 1

Because one const is a local variable of the squareList function, the other const is a global variable holding a squareList. Using the same variable name twice in different scopes is called shadowing, thats sometimes useful but it can also create confusion like in this case.