reactjs - 测试用 TypeScript 编写的自定义 React Hook

我有一个用 TS 编写的自定义 hook useForm，它工作得很好。使用 @testing-library/react-hooks 测试它。测试通过了。但 TypeScript 在一个特定位置抱怨——见下文：

这是自定义钩子：

import { useState } from 'react';

export function useForm<T>(initialValues: T) {
  const [values, setValues] = useState(initialValues);

  return {
    values: values,
    handleChange: (e: React.ChangeEvent<HTMLTextAreaElement | HTMLInputElement>) => {
      setValues({
        ...values,
        [e.target.name]: e.target.value,
      });
    },
    reset: () => setValues(initialValues),
  };
}

这是测试：

import { renderHook, act } from '@testing-library/react-hooks';

import { useForm } from './useForm';

test('should render useForm hook', () => {
  const { result } = renderHook(() =>
    useForm({
      text: 'Note One',
    }),
  );

  expect(result.current).toBeDefined();
  expect(result.current.values.text).toBe('Note One');

  act(() => {
    result.current.handleChange({
      target: { //complains here - Type '{ name: string; value: string; }' is not assignable to type 'EventTarget & (HTMLTextAreaElement | HTMLInputElement)'.
        name: 'text',
        value: 'Note Two',
      },
    });
  });

  expect(result.current.values.text).toBe('Note Two');

  act(() => {
    result.current.reset();
  });
  expect(result.current.values.text).toBe('Note One');
});

这是一个可运行的代码沙箱： https://codesandbox.io/s/flamboyant-curie-6i5moy?file=/src/useForm.test.tsx

答案＃1

我将使用 Event() 构造函数创建一个 change 事件。并通过 Object.defineProperty(event, 'target', {value: {}, writable: false}) 为该事件设置事件目标，也可以参考这个答案。然后使用类型转换 event as unknown as React.ChangeEvent<HTMLInputElement> 来转换事件。

例如

import "@testing-library/react-hooks/lib/dom/pure";
import { renderHook, act } from "@testing-library/react-hooks";

import { useForm } from "./useForm";

test("should render useForm hook", () => {
  const { result } = renderHook(() =>
    useForm({
      text: "Note One"
    })
  );

  expect(result.current).toBeDefined();
  expect(result.current.values.text).toBe("Note One");

  const event = new Event("change");
  Object.defineProperty(event, "target", {
    value: {
      name: "text",
      value: "Note Two"
    },
    writable: false
  });

  act(() => {
    result.current.handleChange(event as unknown as React.ChangeEvent<HTMLInputElement>);
  });

  expect(result.current.values.text).toBe("Note Two");

  act(() => {
    result.current.reset();
  });
  expect(result.current.values.text).toBe("Note One");
});

答案＃2

你可以直接进行类型转换：

 act(() => {
   result.current.handleChange({
     target: {
       name: 'text',
       value: 'Note Two',
     },
   }) as React.ChangeEvent<HTMLTextAreaElement | HTMLInputElement>;
 });