Single Inheritance

Definition

Single inheritance is when a child class inherits from exactly one parent class. It’s the simplest and most common form of inheritance.

All OOP languages support single inheritance.

Characteristics

Aspect	Description
Parents	Exactly one parent class
Children	One or more children (each has one parent)
Complexity	Low — simple and clear hierarchy
Diamond Problem	Not possible
Support	Every OOP language

Example

class Animal {
  constructor(name) {
    this.name = name;
  }

  eat() {
    console.log(`${this.name} is eating`);
  }

  sleep() {
    console.log(`${this.name} is sleeping`);
  }
}

class Dog extends Animal {
  bark() {
    console.log(`${this.name} barks!`);
  }
}

const dog = new Dog("Rex");
dog.eat();   // "Rex is eating" (inherited)
dog.sleep(); // "Rex is sleeping" (inherited)
dog.bark();  // "Rex barks!" (own method)

Visual Diagram

classDiagram
    class Animal {
        +name: string
        +eat() void
        +sleep() void
    }

    class Dog {
        +bark() void
    }

    Animal <|-- Dog : extends

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