javascript - 通用函数类型不适用于返回的对象成员

Question

我正在定义一个函数，它返回一个对象，该对象的成员是具有相同有效负载的函数。有效负载类型通过 generic 定义，它扩展了对象。但是，流提示泛型类型与传递的类型不同:

export const getObj = <T: {}>(url: string) => ({
  create: (entity: T) => console.log(url, entity),
  ...
});

const url = '/some-path';

type TEntity = {
  some: string,
};

const entity: TEntity = {
  some: 'value',
};

const instance = getObj<TEntity>(url);

instance.create(entity);

流提示:

^ Cannot call instance.create with entity bound to entity because TEntity 2 is incompatible with T 2.

Try .

我做错了什么？

Answer 1

如有疑问，be more explicit.

// @flow

type EntityFactory<T> = $ReadOnly<{|
  create: (T) => void,
|}>;

export const getObj = <T>(url: string): EntityFactory<T> => ({
  create: (entity: T) => console.log(url, entity),
});

const url = '/some-path';

type TEntity = {
  some: string,
};

const entity: TEntity = {
  some: 'value',
};

const instance = getObj<TEntity>(url);

instance.create(entity);