const checkThatTwoPlusTwoEqualsFourAMillionTimes = () => { for(let i = 1; i <= 1000000; i++) { if ( (2 + 2) != 4) { console.log('Something has gone very wrong :( '); } } }; // assigning a function to a variable isTwoPlusTwo = checkThatTwoPlusTwoEqualsFourAMillionTimes; isTwoPlusTwo(); console.log(isTwoPlusTwo.name); /// function as Parameters const addTwo = num => { return num + 2; } const checkConsistentOutput = (func, val) => { let checkA = val + 2; let checkB = func(val); if (checkA === checkB){ return checkB; }else{ console.log('inconsistent results'); } } console.log(checkConsistentOutput(addTwo, 5));