代码之家 › 专栏 › 技术社区 › DorkMonstuh

使用它的时候。每一个都会给出一个类型错误笑话

ts-jest jestjs typescript

2

DorkMonstuh · 技术社区 · 4 年前

当我使用它的时候。在为它定义回调时,我从jest中得到的每一个都是一个错误

Argument of type '(n: any) => Promise<void>' is not assignable to parameter of type '() => any'.ts(2345)

代码和它在一起。每一项都概述如下:

it.each([null, undefined, []])('should throw Http exception with expected exception message', async (n) => {
  await expect(() => service.check(n)).rejects.toThrow(
    new HttpException(
      {
        statusCode: HttpStatus.BAD_REQUEST,
        message: "Nothing to check",
        error: HttpStatus.BAD_REQUEST,
      },
      HttpStatus.BAD_REQUEST,
    ),
  );
});

jest类型和jest版本如下所示(如果有帮助):

"@types/jest": "^27.4.1",
"jest": "^27.2.5",

问题在于 async (n) => ... 非常感谢您的帮助,谢谢!

1 回复 | 直到 4 年前

1

0

Sly_cardinal 4 年前

您没有从异步函数返回结果。

异步fat arrow函数是用大括号定义的,这意味着它需要显式的return语句来返回值。

// Curly braces requires explicit return
() => {}

// This doesn't return anything because there is no `return` statement
() => {
  5;
}

// This returns a number
() => {
  return 5;
}

// This fat arrow syntax has an implicit return
() => ()

// These have an implicit return and are equivalent
() => 5
() => (5)

您可以使用显式返回:

// Use explicit return
it.each([null, undefined, []])('should throw Http exception with expected exception message', async (n) => {
  return await expect(() => service.check(n)).rejects.toThrow(
    new HttpException(
      {
        statusCode: HttpStatus.BAD_REQUEST,
        message: "Nothing to check",
        error: HttpStatus.BAD_REQUEST,
      },
      HttpStatus.BAD_REQUEST,
    ),
  );
});

或者去掉花括号。

在第二种情况下,我删除了大括号,并将函数体包装在圆括号中,以使分组更加明确。

// Use implicit return - note curly braces were changed to round brackets
it.each([null, undefined, []])('should throw Http exception with expected exception message', async (n) => (
  await expect(() => service.check(n)).rejects.toThrow(
    new HttpException(
      {
        statusCode: HttpStatus.BAD_REQUEST,
        message: "Nothing to check",
        error: HttpStatus.BAD_REQUEST,
      },
      HttpStatus.BAD_REQUEST,
    ),
  );
));