# 1.1 JavaScript Foundation

Greetings! Let's explore why JavaScript is a powerhouse for web development and get our hands dirty with some foundational coding!

### Why JavaScript?

**1\. Interpreted Nature:** JavaScript is an interpreted language. Unlike compiled languages that need a separate compilation step, JavaScript runs directly in the browser. This not only simplifies the development process but also aids in easy debugging.

**2\. Dynamic and Flexible:** JavaScript is dynamically typed, which means you don't need to specify the data type of a variable. This flexibility allows for faster development and is particularly advantageous in smaller codebases. Unlike statically typed languages like C++, JavaScript adapts on the fly, making it a versatile choice.

*(C++ is better tho, xD)*

**3\. Single-Threaded Nature:** While some consider JavaScript's single-threaded nature a limitation for scalable systems, this design choice ensures a smooth user experience, preventing the browser from freezing during execution. *(No wait, I personally don't like single threaded Nature)*

Now, let's put our newfound knowledge to the test!

### Your First JavaScript Code

1. Open [Repl.it](http://Repl.it) and create a new REPL with the Node.js template.
    
2. In the `index.js` file, write the classic "Hello, World!" program:
    
    ```javascript
    console.log("Hello World");
    ```
    
3. Click on "Run" or navigate to the shell and type `node index.js` to see the output.
    

### JavaScript Fundamentals

#### Simple Primitives:

**Variables (**`let`, `var`, `const`): Variables are containers for storing data values. `let` and `const` are block-scoped, while `var` is function-scoped.

```javascript
let fn = "Rashmin";
let age = 19;
```

**Conditional Statements (**`if-else`): Conditional statements allow us to make decisions in our code.

```javascript
if (age >= 18) {
  console.log("Hello, adult!");
} else {
  console.log("Hey, you're still a minor!");
}
```

#### Complex Primitives:

**Arrays and Objects:** Arrays and objects allow us to organize and store data more efficiently.

```javascript
const ages = [3, 10, 18, 13, 4, 11, 16];
for (let i = 0; i < ages.length; i++) {
  if (ages[i] % 2 === 0) {
    console.log(ages[i] + " ");
  }
}
```

### NOTE:

*We suggest learning JavaScript from YouTube tutorials or documentations. It would be easy if you already know a programming language like C/C++/Java.*

[https://developer.mozilla.org/en-US/docs/Web/JavaScript](https://developer.mozilla.org/en-US/docs/Web/JavaScript)

#### Functions and Callbacks:

**Defining Functions:** Functions are blocks of code designed to perform a particular task.

```javascript
function greet(name) {
  console.log("Hello, " + name + "!");
}

greet("Rashmin");
```

**Callback Functions:** Callback functions are functions passed as arguments to other functions.

```javascript
function processArray(arr, callback) {
  for (let i = 0; i < arr.length; i++) {
    callback(arr[i]);
  }
}

processArray(ages, function (element) {
  console.log("Processing element: " + element);
});
```

## **Explore and learn!**

**1.2 Basic JS APIs** [rashmin.hashnode.dev/dev-1-2](http://rashmin.hashnode.dev/dev-1-2)

**Home article** [https://rashmin.hashnode.dev/dev](https://rashmin.hashnode.dev/dev)