Functions

Question 1

Explain a function

Answer 1

A function is simply a piece of reusable code.

Question 2

What are the three types of functions in JS?

Answer 2

• Function declaration
• Function expression(Anonymous function)
• Arrow function(ES6)

Question 3

Write down a function declaration in JS.

Answer 3

function calcAge(currentYear, birthYear) {
    return currentYear - birthYear;
}

Question 3

What are the differences between function declarations, function expressions & arrow functions in JS?

Answer 3

• Function declarations can be invoked before they are defined as a result of a process called hoisting.(It allows hoisting).
• A function expression is basically a function stored in a variable.
• An arrow function is a special type of function expression that is shorter, introduced in ES6. The arrow function does not have the “this” keyword.

Question 4

Write down a function declaration in JS.

Answer 4

function calcAge(currentYear, birthYear) {
    return currentYear - birthYear;
}

Question 5

Write down a Function expression in JS?

Answer 5

const calcAge = function (currentYear, birthYear) {
    return currentYear - birthYear;
}

Question 6

Write down an arrow function.

Answer 6

const calcAge =(currentYear, birthYear) => currentYear - birthYear;