Concept

Arrow Function is a new feature in Javascript that helps to write shorter and more readable code. Arrow Function provides a concise syntax for declaring functions and mapping parameters and function bodies.

Syntax

Arrow Function is defined using the following syntax:

const functionName = (parameters) => {
  // Phần thân hàm
};

In which:

• const functionName is the function name (can be replaced with let or var).
• parameters are the list of function parameters.
• The function body is placed in curly braces {}.

If the function body has only one return statement, we can write it as follows:

const functionName = (parameters) => expression;

Example of Arrow Function

Here are some examples of using Arrow Function in Javascript:

Example 1: Function that returns the sum of two numbers

const addNumbers = (a, b) => a + b;

console.log(addNumbers(5, 3)); // 8

Example 2: Function to check if a number is even

const isEven = num => num % 2 === 0;

console.log(isEven(4)); // true
console.log(isEven(7)); // false

Example 3: Function to calculate the area of a rectangle

const calculateRectangleArea = (width, height) => width * height;

console.log(calculateRectangleArea(4, 5)); // 20

Example 4: Function to print a list of students to the screen

const students = ['John', 'Emily', 'David'];

const printStudents = () => {
  students.forEach(student => {
    console.log(student);
  });
};

printStudents();
// John
// Emily
// David

Benefits of Arrow Function

Arrow Function brings some benefits when used in Javascript programming:

• Concise syntax: Arrow Function helps to write shorter and more readable code compared to traditional ways.
• Lexical binding: Arrow Function automatically binds the context of the parent function to the child function, avoiding unwanted context changes.
• Does not change the value of this: Arrow Function does not have its own context (lexical this), so there is no need to use .bind(), .call(), or .apply() to change the value of this.

Points to note when using Arrow Function

Although Arrow Function is very useful in many cases, there are also some points to note:

• Cannot use arguments: Arrow Function does not have the arguments object like regular functions, so it cannot access the passed parameters using arguments.
• Not suitable for object methods: Arrow Function does not have its own lexical this context, so it is not suitable for defining object methods.