Enzyme/Jest: Hooks只能在函数组件内部调用

Question

假设我有这样一个组件：

export function Click(props: { counter: number }) {
  const [ counter, setCounter ] = useState(props.counter);

  return (
    <header className="App-header">
      <h1 data-test="counter">{counter}</h1>

      <button onClick={() => setCounter(counter + 1)}>
        Click me
      </button>
    </header>
  );
}

我的测试文件是这样的：

import React from 'react';
import { mount } from "enzyme";
import App, { Click } from './App';

class Setup<Props> {
  constructor(FunctionComponent: React.FC<Props>, props: Props) {
    return mount(
      <>
        {FunctionComponent(props)}
      </>
    )
  }
}

test("Doesn't work", () => {
  const wrapper = new Setup(Click, { counter: 0 });

  expect(wrapper.find(`[data-test="counter"]`)).toHaveLength(1);
});

这returns一个错误： Hooks can only be called inside of the body of a function component.

但是我真的不知道怎么解决。你看，我不能使用功能组件，因为它会破坏目的。我的想法是创建一个库来帮助我编写测试，所以我想使用类.

Answer 1

要成为返回 JSX 的组件函数，应该用作 <Component /> 而不是 Component()。

hooks-rules 医生说：

Don’t call Hooks inside loops, conditions, or nested functions.

Don’t call Hooks from regular JavaScript functions.

不要调用它们，渲染它们。

例如

App.tsx:

import React from 'react';
import { useState } from 'react';

export function Click(props: { counter: number }) {
  const [counter, setCounter] = useState(props.counter);

  return (
    <header className="App-header">
      <h1 data-test="counter">{counter}</h1>

      <button onClick={() => setCounter(counter + 1)}>Click me</button>
    </header>
  );
}

App.test.tsx:

import React from 'react';
import { mount, ReactWrapper } from 'enzyme';
import { Click } from './App';

class Setup<Props> {
  constructor(FunctionComponent: React.FC<Props>, props: Props) {
    return mount(<FunctionComponent {...props} />);
  }
}

describe('68201330', () => {
  test('it should pass', () => {
    const wrapper = new Setup(Click, { counter: 0 }) as ReactWrapper;
    expect(wrapper.find(`[data-test="counter"]`)).toHaveLength(1);
  });
});

测试结果：

 PASS  examples/68201330/App.test.tsx (8.477 s)
  68201330
    ✓ it should pass (31 ms)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |   83.33 |      100 |      50 |   83.33 |                   
 App.tsx  |   83.33 |      100 |      50 |   83.33 | 11                
----------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        9.331 s, estimated 10 s

Enzyme/Jest: Hooks只能在函数组件内部调用

Enzyme/Jest: Hooks can only be called inside of the body of a function component

typescript

reactjs

jestjs

enzyme

react-hooks