Arrow functions, also known as lambda functions, are a shorthand way of writing function expressions in JavaScript. They were introduced in ECMAScript 6 (ES6) and provide a concise way to define functions.

Here's the syntax for arrow functions:

(parameters) => { statement }

Or for a single statement:

(parameters) => statement

The parameters can be one or more and are enclosed in parentheses. If there's only one parameter, the parentheses can be omitted. The arrow (=>) separates the parameters from the function body. If the function body consists of a single statement, the curly braces can be omitted.

Here are some examples of arrow functions:

// Simple arrow function with no parameters
const hello = () => {
console.log("Hello!");
};
 
// Arrow function with one parameter
const greet = (name) => {
console.log(Hello, ${name}!);
};
 
// Arrow function with multiple parameters
const add = (a, b) => {
return a + b;
};
 
// Arrow function with single-line return statement
const multiply = (a, b) => a * b;

In the first example, we define a simple arrow function that logs "Hello!" to the console. Since there are no parameters, we leave the parentheses empty.

In the second example, we define an arrow function that takes a single parameter (name) and uses string interpolation to log a greeting with the name.

In the third example, we define an arrow function that takes two parameters (a and b) and returns their sum. Since the function body contains multiple statements, we enclose it in curly braces and use a return statement.

In the fourth example, we define an arrow function that takes two parameters (a and b) and returns their product. Since the function body consists of a single return statement, we can omit the curly braces and the return keyword.

Arrow functions are particularly useful for writing concise and clear code. They are commonly used in functional programming and are often used as callback functions. However, it's important to note that they have some limitations compared to traditional functions, such as not having their own this binding.