Learning Functions in Basic Javascript

Saturday, March 11, 2023

Introduction Function in Javascript Basics

buayaberdiri.blogspot.com - Functions are a fundamental concept in JavaScript, as they allow you to encapsulate and reuse code in a modular way. In this article, we'll cover the basics of functions in JavaScript, including how to define, call, and use them in your code.

Defining a function

A function in JavaScript is defined using the function keyword, followed by the function name, a list of parameters (optional), and the function body enclosed in curly braces. Here's an example:

function greet(name) {
  console.log(`Hello, ${name}!`);
}

In this example, we've defined a function called greet that takes a single parameter called name. The function body simply logs a message to the console using template literals.

Calling a function

Once a function is defined, you can call it by using its name followed by parentheses, passing in any arguments if required. For example, to call the greet function we defined earlier, we can do:

greet('John'); // Output: Hello, John!

This will output the message "Hello, John!" to the console.

Returning a value

Functions in JavaScript can also return a value using the return keyword. Here's an example:

function square(num) {
  return num * num;
}

In this example, we've defined a function called square that takes a single parameter called num. The function body returns the square of the parameter by multiplying it by itself.

To use the square function, we can call it and store the result in a variable:

const result = square(5);
console.log(result); // Output: 25

This will output the value 25 to the console.

Introduction About Arrow functions in Javascript

In addition to the traditional function syntax shown above, JavaScript also has a shorthand syntax called arrow functions. Arrow functions are a more concise way to define functions that take a single expression as their body. Here's an example:

const square = num => num * num;

This defines an arrow function called square that takes a single parameter called num. The function body returns the square of the parameter by multiplying it by itself.

To use the square function, we can call it and store the result in a variable:

const result = square(5);
console.log(result); // Output: 25

This will output the value 25 to the console.

Higher-order functions

In JavaScript, functions can be passed as arguments to other functions and returned as values from functions. Functions that take other functions as arguments or return functions as values are called higher-order functions.

Here's an example of a higher-order function that takes a function as its argument and calls it multiple times:

function repeat(func, num) {
  for (let i = 0; i < num; i++) {
    func();
  }
}

In this example, we've defined a function called repeat that takes two parameters: a function called func and a number called num. The function body uses a for loop to call the func function num times.

To use the repeat function, we can define a function to pass as the func argument:

function sayHello() {
  console.log('Hello!');
}

repeat(sayHello, 3); // Output: Hello! Hello! Hello!

This will output the message "Hello!" to the console three times.

Conclusion

Functions are a powerful feature of JavaScript that allow you to write reusable code in a modular way. By defining functions, you can encapsulate functionality and call it from other parts

See the article about javascript here:

Check out other articles about HTML & CSS:

Buaya Terbang Blog