design-patterns

Strategy Pattern

The Strategy Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable.
Strategy lets the algorithmm vary independently from the client that use it.

// Implementation code
abstract class Animal {}

class Dog extends Animal {
    bark(): void {
        console.log('Bhaw')
    }
}

const dog = new Dog();
dog.bark()

// Interface Code

interface SoundBehavior {
    performSound(): void
}

class Bark implements SoundBehavior {

    performSound(): void {
        console.log('Bhaw')
    }
}

class Animal {
    soundBehavior: SoundBehavior;

    makeSound(): void {
        this.soundBehavior.performSound();
    }
}


class Dog extends Animal {
    
    constructor() {
        this.soundBehavior = new Bark();
    }
}

function getAnimal(): Animal {
    return new Dog();
}


const animal = getAnimal();
animal.makeSound();

It is now much easier to add multiple behaviors in the “family of algorithms”.

Typescript Learnings

We need to use the following compiler option to compile Abstract Duck Class to avoid error without initializing.
Refer

    "compilerOptions": {
        "strictPropertyInitialization": false,
        ...
    }