Arrow functions

What is an arrow function?

An arrow function uses => in place of the function keyword. It can make a small function more concise, although not every function can be shortened in the same way.

Basic structure

The general form is:

const functionName = (parameter1, parameter2) => {
  // Statements to execute
}

For example:

//example
const ong = (x, y) => {
	return x + y
}

If the body only returns a single expression, we can omit both the braces and return:

//example
const ong = (x, y) => x + y

If the body contains additional statements, such as a separate console.log call before the return, it cannot be shortened in that same way.

A single parameter

When there is only one simple parameter rather than two, its parentheses can also be omitted:

// With one parameter

const ong = x => x + 1

Editorial note: this lesson focuses on syntax. Arrow functions also differ from ordinary functions in behavior, including their handling of this, so they are not interchangeable in every situation. The generic syntax example's Korean placeholder names have been translated.