교집합 타입

interface를 사용하면 다른 타입을 확장하여 새로운 타입을 만들 수 있습니다. 타입스크립트에서는 기존 객체 타입을 결합할 때 주로 사용하는 교집합 타입도 제공합니다.

교집합 타입은 & 연산자를 사용하여 정의됩니다.

ts
interface Colorful {
  color: string;
}
interface Circle {
  radius: number;
}
 
type ColorfulCircle = Colorful & Circle;

ts
interface Colorful {
  color: string;
}
interface Circle {
  radius: number;
}
 
type ColorfulCircle = Colorful & Circle;

여기서는 Colorful과 Circle을 교차시켜 Colorful과 Circle의 모든 멤버가 포함된 새로운 타입을 만듭니다.

ts
function draw(circle: Colorful & Circle) {
  console.log(`Color was ${circle.color}`);
  console.log(`Radius was ${circle.radius}`);
}
 
// 문제없습니다.
draw({ color: "blue", radius: 42 });
 
// 이런!
draw({ color: "red", raidus: 42 });
Argument of type '{ color: string; raidus: number; }' is not assignable to parameter of type 'Colorful & Circle'.
  Object literal may only specify known properties, but 'raidus' does not exist in type 'Colorful & Circle'. Did you mean to write 'radius'?2345Argument of type '{ color: string; raidus: number; }' is not assignable to parameter of type 'Colorful & Circle'.
  Object literal may only specify known properties, but 'raidus' does not exist in type 'Colorful & Circle'. Did you mean to write 'radius'?

ts
function draw(circle: Colorful & Circle) {
  console.log(`Color was ${circle.color}`);
  console.log(`Radius was ${circle.radius}`);
}
 
// 문제없습니다.
draw({ color: "blue", radius: 42 });
 
// 이런!
draw({ color: "red", raidus: 42 });
Argument of type '{ color: string; raidus: number; }' is not assignable to parameter of type 'Colorful & Circle'.
  Object literal may only specify known properties, but 'raidus' does not exist in type 'Colorful & Circle'. Did you mean to write 'radius'?2345Argument of type '{ color: string; raidus: number; }' is not assignable to parameter of type 'Colorful & Circle'.
  Object literal may only specify known properties, but 'raidus' does not exist in type 'Colorful & Circle'. Did you mean to write 'radius'?