Why Method overriding in Javascript? - Purpose & Use Cases

The Big Idea

What if you could change just one action in your program without rebuilding everything from scratch?

The Scenario

Imagine you have a basic toy robot that can say "Hello". Now, you want a new robot that says "Hello" but also adds "I am your helper." If you had to build a whole new robot from scratch just to change this one behavior, it would take a lot of time and effort.

The Problem

Manually rewriting or copying all the robot's features just to change one small behavior is slow and error-prone. You might forget some features or introduce bugs. It's like rewriting the whole recipe just to add a pinch of salt.

The Solution

Method overriding lets you keep the original robot's features but change just the part you want. You create a new robot that uses the old one's abilities but replaces the "sayHello" action with your own version. This saves time and keeps your code clean.

Before vs After

✗ Before

class Robot {
  sayHello() {
    console.log('Hello');
  }
}

class NewRobot {
  sayHello() {
    console.log('Hello');
    console.log('I am your helper.');
  }
  // Need to rewrite all other methods too
}

✓ After

class Robot {
  sayHello() {
    console.log('Hello');
  }
}

class NewRobot extends Robot {
  sayHello() {
    super.sayHello();
    console.log('I am your helper.');
  }
}

What It Enables

It enables you to customize or improve specific behaviors in your programs without rewriting everything, making your code smarter and easier to maintain.

Real Life Example

Think of a video game where the basic character can walk and jump. A new character might walk and jump differently or add new moves. Method overriding lets the new character keep the basic moves but change how they work.

Key Takeaways

Method overriding lets you change specific behaviors in inherited code.

It avoids rewriting entire classes, saving time and reducing errors.

It helps create flexible and maintainable programs.