javascript - 更新以响应 16.2.0 时的碎片不起作用

Question

我将我的 React 版本更新到 16.2.0，并使用 Fragment 来包装一些组件。所以我写:

import React from 'react;

然后我写:

const CustomerSearch = () => (
 <React.Fragment>
        <Field
          id="lastname"
          name="lastname"
          floatingLabelText="ΕΠΩΝΥΜΟ"
          floatingLabelStyle={styles.floatingLabelStyle}
          floatingLabelFocusStyle={styles.floatingLabelFocusStyle}
          underlineStyle={styles.underlineStyle}
          underlineFocusStyle={styles.underlineFocusStyle}
          component={InputTextField}
        />
        <br />
        <Field
          id="firstname"
          name="firstname"
          floatingLabelText="ΟΝΟΜΑ"
          floatingLabelStyle={styles.floatingLabelStyle}
          floatingLabelFocusStyle={styles.floatingLabelFocusStyle}
          underlineStyle={styles.underlineStyle}
          underlineFocusStyle={styles.underlineFocusStyle}
          component={InputTextField}
        />
        <br />
        <Field
          id="companyName"
          name="companyName"
          floatingLabelText="ΟΝΟΜΑ ΕΤΑΙΡΕΙΑΣ"
          floatingLabelStyle={styles.floatingLabelStyle}
          floatingLabelFocusStyle={styles.floatingLabelFocusStyle}
          underlineStyle={styles.underlineStyle}
          underlineFocusStyle={styles.underlineFocusStyle}
          component={InputTextField}
        />
        <br />
        <Field
          id="mobile"
          name="mobile"
          floatingLabelText="ΚΙΝΗΤΟ"
          floatingLabelStyle={styles.floatingLabelStyle}
          floatingLabelFocusStyle={styles.floatingLabelFocusStyle}
          underlineStyle={styles.underlineStyle}
          underlineFocusStyle={styles.underlineFocusStyle}
          component={InputTextField}
        />
        <br />
        <Field
          id="generatorSN"
          name="generatorSN"
          floatingLabelText="GENERATOR SN"
          floatingLabelStyle={styles.floatingLabelStyle}
          floatingLabelFocusStyle={styles.floatingLabelFocusStyle}
          underlineStyle={styles.underlineStyle}
          underlineFocusStyle={styles.underlineFocusStyle}
          component={InputTextField}
        />
        <br />
      </React.Fragment>
)

export default CustomerSearch

但我收到一个错误:

Warning: React.createElement: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in. Check the render method of CustomerSearch.

为什么会这样？我使用了一个 div，它运行良好。谢谢

Answer 1

问题出在依赖项上。我跑了 npm install npm@latest -g我的问题已解决 :)