UnionTypeはclassのinterfaceとして使えない[TypeScript]

現象

typeをimplementsしようとすると、以下のエラーが出た。

A class can only implement an object type or intersection of object types with statically known members.

原因

どうやらUnionTypeはimplementsできないらしい。

stackoverflow.com

サンプル

type Human = {
    head: any;
    hands: any
    legs: any;
}

type Hourse = {
    legs: any
    tail: any
}

type Therianthrope = Human | Hourse;

class Kentauros implements Therianthrope {
    head: any;
    hands: any
    legs: any;
    tail: any
}

playgroundで試した結果↓

TypeScript: TS Playground - An online editor for exploring TypeScript and JavaScript

解決策

interfaceのextendsができる。

interface Human {
    head: any;
    hands: any
    legs: any;
}

interface Hourse {
    legs: any
    tail: any
}

interface Therianthrope extends Human, Hourse {}

class Kentauros implements Therianthrope {
    head: any;
    hands: any
    legs: any;
}

TypeScript: TS Playground - An online editor for exploring TypeScript and JavaScript