Open theKashey opened 5 years ago
Hi @theKashey!
Can you clarify things a bit more. It's not clear to me what is and isn't working based on your example repo and the scenario's you've posted. I don't know what "require foo.mjs
" or "require index.js
" means in this scenario.
spec.js
provides a simple config
rewiremock('./foo').withDefault(() => 'fake-foo'); // mock `foo`
index = (await import('./index')).default; // require `index`
Then I am trying to run different scenarios manually renaming files.
js
foo.mjs
is working. Ie still goes thought Module._load
foo.mjs
via index.js
is working.foo.mjs
via index.mjs
is not working. Look like in case of mjs
Module._load is working only for a first file. Later it uses something another.Thank you!
Ideally mocking shouldn't work for .mjs
at all. What you've uncovered is gaps in our limitation logic to prevent it. So my fixes here would just be making all of the existing places where mocking .mjs
works prevented.
🤯 So - the old ways to mock are dying, but what about new ways? Loaders hooks and loaders maps could handle it, but not in a test-friendly way.
As long as (module-level) dependency mocking is an essential part of any testing - it shall be possible. We don't have any other variant (sinon stubbing is not a variant).
The .mjs
file extension has always lacked esm
option support. So these thing that you thought were possible were really never intended for .mjs
. Stubbing/spys and mocking work fully with .js
.
Yep. That's why I am asking for advice. Right now it makes .mjs
impossible to use. I am quite addicted to dependency mocking, and think that it's a good pattern, and without proper support would have to migrate to more classical DI, which would make everything more classish and complex (as seen in Java).
There should be a way to mock mjs
.
When Node officially supports mocking then you can I guess. For esm
you can always use .js
. If you insist on .mjs
you're likely going to have a bad time across multiple tools beyond esm
though.
Ok, so I have to open issue for a node/modules
until it's not too late.
The problem is tracked elsewhere - https://github.com/nodejs/modules/issues/98
Thanks @theKashey!
But there's still a consistency issue on our end to track 😸
Let's define two files -
foo
andindex
. Then lets mock them usingModule._load
based mocker.Scenario 1 - all
.js
foo.js
to returnbar
foo.js
- 👍index.js
- 👍Scenario 2 -
foo.mjs
+index.js
foo.mjs
to returnbar
foo.mjs
- 👍index.js
- 👍Scenario 3 -
foo.mjs
+index.mjs
foo.mjs
to returnbar
foo.mjs
- 👍index.mjs
- 👎 <<---------, whilefoo.mjs
is still mocked.Scenario 3 -
foo.js
+index.mjs
Probably this is a feature, not a bug. But how then mock
.mjs
?Example: https://github.com/theKashey/rewiremock-esm-repro