Question

例如，我正在使用Archiver：

archive.on('error', err => {
  if (typeof callback === 'function') {
    callback.call(this, err);
  } else {
    throw err;
  }
});

根据玩笑，发现这些行。您如何发出此错误？模拟吗？

Answer 1

您可以将回调移动到其他模块，然后将其导出，例如：

@echo off & cls
:setnum
set /p %ynum%=Pick a Number: 
:start
echo This is your number: %ynum%
timeout /t 1 /nobreak > NUL
goto start

然后您可以将其导入到主文件中：

//calbacks.js

const errorCallback = callback => err => {
  if (typeof callback === 'function') {
    callback.call(this, err);
  } else {
    throw err;
  }
}

export {errorCallback} // es6 named export

您也可以将其导入import { errorCallback } from "./callbacks.js" //path should be correct, this would work if you have both files in same directory ... archive.on('error', errorCallback(callback)) //pass callback to curried function并进行测试：

spec

并测试回调不起作用的情况：

const spy = jest.fn()

errorCallback(fn)("error")    
expect(spy).toBeCalledWith("error");

如何在玩笑和打字稿中发出错误事件

1 个答案: