타입스크립트)제너릭(Generics)

 

class ArrayOfNumbers {

  constructor(public collection: number[]) {}

  get(index: number): number {

    return this.collection[index];

  }

}

class ArrayOfStrings {

  constructor(public collection: string[]) {}

  get(index: number): string {

    return this.collection[index];

  }

}

//Generic을 적용함

class ArrayOfAnything<T> {

  constructor(public collection: T[]) {}

  get(index: number): T {

    return this.collection[index];

  }

}

const arr = new ArrayOfAnything(['a', 'b', 'c']);

///////////////////////

function printStrings(arr: string[]): void {

  for (let i = 0; i < arr.length; i++) {

    console.log(arr[i]);

  }

}

function printNumbers(arr: number[]): void {

  for (let i = 0; i < arr.length; i++) {

    console.log(arr[i]);

  }

}

//Generic을 적용함

function printAnything<T>(arr: T[]): void {

  for (let i = 0; i < arr.length; i++) {

    console.log(arr[i]);

  }

}

printAnything<string>(['a', 'b', 'c']);

///////////////////////

//Generic Constraints

class Car {

  print() {

    console.log('I am a car');

  }

}

class House {

  print() {

    console.log('I am a house');

  }

}

interface Printable {

  print(): void;

}

function printHousesOrCars<T extends Printable>(arr: T[]): void {  // Printable를 상속하는 T만 오도록 제한한 것

  for (let i = 0; i < arr.length; i++) {

    arr[i].print();

  }

}

printHousesOrCars<House>([new House(), new House()]);

printHousesOrCars<Car>([new Car(), new Car()]);