如何在 Node.js 中实例化一个新的 SystemError 对象？

Question

Looking at Node's documentation , SystemError extends the Error class. However, if you attempt to use SystemError directly, Node will throw a ReferenceError saying that SystemError is undefined.

Clearly, according to the docs, it is possible to encounter an instance of SystemError , but it seems impossible to recreate such an error in the usual way (eg throw new SystemError(args) ).

I would like to test some code which is designed to interact with the specified SystemError API as detailed in the docs, but I have no idea how to recreate a SystemError . Is this even possible?

Answer 1

I think that node.js doesn't put SystemError available in order to avoid anyone (npm packages) to use it. So a SystemError is really a SystemError and not something else.

If you want to test it, generate the error : Try to read a file that doesn't exist for example.

An other soluce would be to recreate a lookalike error because you know every property of it. But it's a workaround actually.

https://nodejs.org/api/errors.html#errors_class_systemerror

In the Github https://github.com/DefinitelyTyped/DefinitelyTyped I couldn't find any interface declaration of SystemError .

Except custom implementations made by node-fetch , voximplant-websdk and alexa-sdk .

https://github.com/DefinitelyTyped/DefinitelyTyped/search?q=systemError&unscoped_q=systemError