functions.js

// ==== Callbacks ====

/* Step 1: Create a higher-order function that accepts a callback
 * Create a higher-order function named consume that can take 3 parameters.
 * The first two parameters can accept any argument
 * The last parameter accepts a callback
 * In the body of the function return the callback with the two parameters that you created
 */
function consume(param1, param2, cb) {
  return cb(param1, param2);
}

/* Step 2: Create several functions to callback with consume();
 * Create a function named add that returns the sum of two numbers
 * Create a function named multiply that returns the product of two numbers
 * Create a function named greeting that accepts a first and last name and returns "Hello first-name last-name, nice to meet you!"
 */
function add(param1, param2) {
  console.log(param1 + param2);
}

function multiply(param1, param2) {
  console.log(param1 * param2);
}

function greeting(param1, param2) {
  console.log(`Hello ${param1} ${param2}, nice to meet you!`);
}

/* Step 3: Check your work by un-commenting the following calls to consume(): */
consume(2, 2, add); // 4
consume(10, 16, multiply); // 160
consume("Mary", "Poppins", greeting); // Hello Mary Poppins, nice to meet you!

// ==== Closures ====

// Explain in your own words why `nestedfunction()` can access the variable `internal`.

// Explanation: because nestedFunction() is inside the scope of myFunction and has access to 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();