Functions · Lesson 15 of 45

Arrow functions

A shorter way to write functions, and when not to.

6 minutes4 games

An arrow function is a shorter function: (params) => body. If the body is a single expression, its result is returned with no return or { }. With exactly one parameter the brackets are optional.

JavaScript

const square = n => n * n
const add = (a, b) => a + b
const greet = () => "Hello!"
const describe = (name, age) => {
  const group = age >= 18 ? "adult" : "minor"
  return `${name} is an ${group}`
}

console.log(square(6), add(2, 3), greet())
console.log(describe("Nour", 20))

Quick question

const add = (a, b) => a + b… what does add(2, 3) return?

What's the output?

const f = (x) => { x * 2 }
console.log(f(5))

What will this code print?

Order the lines

Order it to print true when the number is above 10.

Click the lines in the right order

Exercise

Write an arrow function toCelsius converting Fahrenheit: (f - 32) * 5 / 9, then print toCelsius(212).

Expected output: 100

JavaScript

Learn more from

Played 0 of 4 games

JavaScript

Functions · Lesson 15 of 45

Arrow functions

A shorter way to write functions, and when not to.

6 minutes4 games

JavaScript

const square = n => n * n
const add = (a, b) => a + b
const greet = () => "Hello!"
const describe = (name, age) => {
  const group = age >= 18 ? "adult" : "minor"
  return `${name} is an ${group}`
}

console.log(square(6), add(2, 3), greet())
console.log(describe("Nour", 20))

Quick question

const add = (a, b) => a + b… what does add(2, 3) return?

What's the output?

const f = (x) => { x * 2 }
console.log(f(5))

What will this code print?

Order the lines

Order it to print true when the number is above 10.

Click the lines in the right order

Exercise

Write an arrow function toCelsius converting Fahrenheit: (f - 32) * 5 / 9, then print toCelsius(212).

Expected output: 100

JavaScript

Learn more from

Played 0 of 4 games