Taki

Posted on Apr 27

Bridge Pattern

#javascript #beginners #webdev #programming

📖 What is the Bridge Pattern? (Simple Explanation)

Bridge Pattern means:

"Separate abstraction from implementation so they can evolve independently."

➡️ Instead of tying two things together tightly (hard-coded),

you connect them through a “bridge” interface.

Think about it like remotely controlling something:

The remote control (abstraction)
The TV (implementation)

They work together, but you could swap either one independently.

🎨 Real-World Examples (Easy to Visualize)

🎮 1. Game Controller

Abstraction: Controller (buttons, joysticks)
Implementation: Different consoles (Xbox, PlayStation, Switch)

✅ You can use a controller to operate different consoles if they speak the same "control" language.

🖥️ 2. UI Themes

Abstraction: UI Components (Button, Modal, Card)
Implementation: Light Theme, Dark Theme, Neon Theme

✅ You can swap the theme without rewriting components.

🚗 3. Vehicle and Engine

Abstraction: Vehicle (Car, Truck)
Implementation: Engine (PetrolEngine, ElectricEngine)

✅ You can change engines without rebuilding the whole vehicle class.

🖥️ TypeScript Code Example — Remote Control and Devices

Imagine:

Remote controls devices (TV, Radio)
Devices can be switched on/off independently.

1. Define the Implementation Interface

// Bridge Interface
interface Device {
  turnOn(): void;
  turnOff(): void;
}

2. Concrete Implementations

class TV implements Device {
  turnOn() {
    console.log("TV is now ON");
  }
  turnOff() {
    console.log("TV is now OFF");
  }
}

class Radio implements Device {
  turnOn() {
    console.log("Radio is now ON");
  }
  turnOff() {
    console.log("Radio is now OFF");
  }
}

3. Define the Abstraction

class RemoteControl {
  constructor(protected device: Device) {}

  turnDeviceOn() {
    this.device.turnOn();
  }

  turnDeviceOff() {
    this.device.turnOff();
  }
}

4. Use It

const tv = new TV();
const radio = new Radio();

const tvRemote = new RemoteControl(tv);
tvRemote.turnDeviceOn();   // TV is now ON

const radioRemote = new RemoteControl(radio);
radioRemote.turnDeviceOff(); // Radio is now OFF

🎯 Why Use Bridge Pattern?

✅ Reduce code duplication

✅ Separate concerns (logic vs. implementation)

✅ Swap implementations easily (like device types, database drivers, themes)

✅ Extend without fear (add new devices or new remote functions separately)

✅ Real-World Practical Uses of Bridge

Real-world example	Bridge usage
Database Drivers	Abstract `DatabaseClient` (PostgreSQL, MongoDB, MySQL)
Payment Gateways	Abstract `PaymentService` (Stripe, PayPal, Apple Pay)
Cloud Storage	Abstract `StorageService` (AWS S3, Google Cloud, Azure Blob)
Frontend Themes	Abstract `Theme` (Light, Dark, Custom)
Media Players	Abstract `Player` (MP3, MP4, WAV)

📌 Visual Diagram

RemoteControl (Abstraction)
       |
    [uses]
       ↓
TV / Radio (Implementation)

➡️ RemoteControl doesn’t care what device it controls, as long as it matches the Device interface.

📦 Key Pattern Structure (Quick Summary)

// Implementation Interface
interface Implementor { method(): void; }

// Concrete Implementation
class ConcreteImplementorA implements Implementor { method() {} }
class ConcreteImplementorB implements Implementor { method() {} }

// Abstraction
class Abstraction {
  constructor(protected implementor: Implementor) {}

  operation() {
    this.implementor.method();
  }
}

🚀 Important Tip for Senior-Level Usage

When designing large systems:

Use Bridge if your abstractions and implementations both need to grow independently.
It's better than subclass explosion (too many hardcoded variations).

✅ Flexible, Extensible, and SOLID-friendly!

🌟 Final Summary in One Line

"Bridge pattern separates what you do from how you do it."

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