What is class in JavaScript ? How to define and use it?

class MyClass {
  constructor(prop1, prop2) {
    this.property1 = prop1;
    this.property2 = prop2;
  }

  method1() {
    console.log('Method 1 executing');
  }

  method2() {
    console.log('Method 2 executing');
  }
}
```text

In this example:
- `MyClass` is the name of the class.
- `constructor` is a special method for creating and initializing objects created with a class. It is executed automatically when a new object is created with the `new` keyword. 
- `method1` and `method2` are methods of the class, defining behaviour for instances of the class. 

## Creating an Instance

To create an instance of a class, you use the `new` keyword:

```javascript
const obj = new MyClass('value1', 'value2');
```text

This creates a new object `obj` based on the `MyClass` blueprint, with `property1` set to `'value1'` and `property2` set to `'value2'`. 

## Accessing Properties and Methods

You can then access properties and methods of the object using dot notation:

```javascript
console.log(obj.property1); // Output: 'value1'
obj.method1();              // Output: 'Method 1 executing'
```text

## Inheritance

Classes in JavaScript also support inheritance. You can use the `extends` keyword to create a subclass:

```javascript
class SubClass extends MyClass {
  constructor(prop1, prop2, prop3) {
    super(prop1, prop2);
    this.property3 = prop3;
  }

  method3() {
    console.log('Method 3 executing');
  }
}
```text

Happy coding!