Can multiple inheritance be used in TypeScript?

In TypeScript, multiple inheritance of classes is not directly supported, meaning a class cannot inherit from multiple classes simultaneously. This is because JavaScript (on which TypeScript is based) only supports single inheritance.

However, in TypeScript, you can implement a semblance of multiple inheritance using mixins — functions that add functionality to a class.

Example of a mixin:

class CanEat {
  eat() {
    console.log('Eating');
  }
}

class CanWalk {
  walk() {
  console.log('Walking');
  }
}

class Person {}

interface Person extends CanEat, CanWalk {}

applyMixins(Person, [CanEat, CanWalk]);

function applyMixins(derivedCtor: any, baseCtors: any[]) {
  baseCtors.forEach(baseCtor => {
    Object.getOwnPropertyNames(baseCtor.prototype).forEach(name => {
      derivedCtor.prototype[name] = baseCtor.prototype[name];
    });
  });
}

const p = new Person();
p.eat(); // Eating
p.walk(); // Walking

Thus, multiple inheritance is achieved through composition and mixins, not through direct inheritance of multiple classes.