React和Typescript -由于类型错误“将类型'Global & typeof globalThis‘转换为类型’GLOBALWithFetchMock...‘，测试失败...”

Question

使用React和Typescript非常棒，但有时会导致令人费解的问题。在本例中，我的所有测试都失败了，并出现了与jest-fetch-mock相关的相同错误：

> 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文件中没有任何更改，因此可能是由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，但没有任何变化。

Answer 1

如果您在setUpTests.ts中将GlobalWithFetchMock声明为全局类型，而Typescript仍然出错，请尝试将全局类型包装在方括号"()“中，并将初始设置为unknown

修改自

const customGlobal: GlobalWithFetchMock = global as GlobalWithFetchMock

至

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

您应该能够成功地再次运行您的测试，并显示许多绿色标记：)