HIGHER-ORDER FUNCTIONS: Functions as Parameters


Tue Oct 05 2021 11:44:37 GMT+0000 (UTC)

Saved by @ianvalentino #javascript

const checkThatTwoPlusTwoEqualsFourAMillionTimes = () => {
  for(let i = 1; i <= 1000000; i++) {
    if ( (2 + 2) != 4) {
      console.log('Something has gone very wrong :( ');

const addTwo = num => num + 2;

const timeFuncRuntime = funcParameter => {
  let t1 = Date.now();
  let t2 = Date.now();
  return t2 - t1;

// Write your code below

const time2p2 = timeFuncRuntime(checkThatTwoPlusTwoEqualsFourAMillionTimes);

const checkConsistentOutput = (func, val) => {
    let firstTry = func(val);
    let secondTry = func(val);
    if (firstTry === secondTry) {
        return firstTry
    } else {
        return 'This function returned inconsistent results'

console.log(checkConsistentOutput(addTwo, 10));

"Since functions can behave like any other type of data in JavaScript, it might not surprise you to learn that we can also pass functions (into other functions) as parameters. A higher-order function is a function that either accepts functions as parameters, returns a function, or both! We call the functions that get passed in as parameters and invoked callback functions because they get called during the execution of the higher-order function. When we pass a function in as an argument to another function, we don’t invoke it. Invoking the function would evaluate to the return value of that function call. With callbacks, we pass in the function itself by typing the function name without the parentheses (that would evaluate to the result of calling the function)."