React 和 Typescript - 由于类型错误“将类型 'Global & typeof globalThis' 转换为类型 'GlobalWithFetchMock'...”而导致测试失败答案

【问题标题】：React and Typescript - Tests are failing due to type error "Conversion of type 'Global & typeof globalThis' to type 'GlobalWithFetchMock'..."React 和 Typescript - 由于类型错误“将类型 'Global & typeof globalThis' 转换为类型 'GlobalWithFetchMock'...”而导致测试失败
【发布时间】：2021-06-25 16:02:24
【问题描述】：

使用 React 和 Typescript 非常棒，但有时会导致令人头疼的问题。在这种情况下，我的所有测试都因与 jest-fetch-mock 相关的相同错误而失败：

> NODE_ENV=test jest
 FAIL  src/store/index.test.tsx
  ● Test suite failed to run
    src/setupTests.ts:6:43 - error TS2352: Conversion of type 'Global & typeof globalThis' to type 'GlobalWithFetchMock' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
      Property 'fetchMock' is missing in type 'Global & typeof globalThis' but required in type 'GlobalWithFetchMock'.
    6 const customGlobal: GlobalWithFetchMock = global as GlobalWithFetchMock
                                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      node_modules/jest-fetch-mock/types/index.d.ts:15:5
        15     fetchMock: FetchMock;
               ~~~~~~~~~
        'fetchMock' is declared here.

setupTests.ts 文件没有变化，所以可能是由于某些依赖项的更新引起的。我尝试删除 node_modules 并重新安装，清除缓存并更改节点版本，但没有任何改变。

【问题讨论】：

标签： javascript reactjs typescript unit-testing jest-fetch-mock

【解决方案1】：

如果您在 setUpTests.ts 中将 GlobalWithFetchMock 声明为全局类型，并且 Typescript 仍在抱怨，请尝试将全局类型括在括号“()”中并最初设置为 unknown

修改自

const customGlobal: GlobalWithFetchMock = global as GlobalWithFetchMock

到

const customGlobal: GlobalWithFetchMock = (global as unknown) as GlobalWithFetchMock

您应该能够再次成功运行测试，并带有大量绿色：)

【讨论】：