Add globalThis.fetch

[takurinton]

I had this conversation with @developit on Twitter.
https://twitter.com/_developit/status/1558610677157269504

wmr gives an error if there is no fetch when prerendering.
To work around this, define globalThis.fetch in preact-iso's prerender.

[changeset-bot]

🦋 Changeset detected

Latest commit: c0b0b1b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
wmr	Minor

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[takurinton]

@developit

I am wondering if I should include the following DOMParser in the init() function. What do you think?

globalThis.DOMParser = new (require("jsdom").JSDOM)("").window.DOMParser;

[rschristian]

This should be done in WMR's prerender rather than preact-iso: https://github.com/preactjs/wmr/blob/main/packages/wmr/src/lib/prerender.js

We set a couple other things on globalThis there, as you can see.

Edit: To expand a little, preact-iso isn't tied to WMR. It very well could be used in other environments. As such, if we want to fix a shortcoming in WMR specifically, we'll want to move this into WMR's prerender script.

This also allows us to pass config values, like the output directory, easily.

[takurinton]

@rschristian

To expand a little, preact-iso isn't tied to WMR.

Okay, I was a little mistaken. I thought this was all inclusive.
And I have completed porting globalThis.fetch to the wmr code and have confirmed that it also passes CI.

[rschristian]

Totally fair! To be honest it's in a bit of a weird spot right now. We'd like people to use it for more than just WMR, but, being buried in this monorepo, a lot of people don't even know it exists (we're working on fixing that though).

Could we add a test case for this? Super simple fetch for markdown, like you do in your blog, would be awesome!

You can add a test fixture here: https://github.com/preactjs/wmr/tree/main/packages/wmr/test/fixtures
And a test case here: https://github.com/preactjs/wmr/blob/main/packages/wmr/test/production.test.js#L762

Just need to build & prerender the fixture then check that the prerendered HTML contains our markdown content.

[takurinton]

@rschristian
I'm new to wmr core and still don't have the full picture and completely forgot about tests.
I'll get to it right away!! Thank you!!

[takurinton]

@rschristian
One test is failing, but the rest are passing. All tests passed!!
Can this PR be merged? Also is there anything else I can do? Thank you.

[rschristian]

Nearly forgot, needs a changeset.

You can run yarn changeset from the root of the repo to open a CLI for creating a changeset, which is a description of the change the PR provides (goes into forming the changelog). I'd probably mark this as a minor due to the added functionality.

I can get around to doing this later & merging too.

Edit: Indeed, we seem to have a flakey test. Took me a few reruns before everything passed without issue.

[takurinton]

@rschristian
Thanks for the changeset change!
I'm at work right now and wasn't able to respond. Appreciate it!

[rschristian]

Thanks!

[danielweck]

Indeed, we seem to have a flakey test. Took me a few reruns before everything passed without issue.

Possibly related?

• Prerendering not working on Node 16 #896 (comment)
• Build segfaults on Node.js v16 if config contains empty middleware array #893 (comment)

[rschristian]

@danielweck Actually no, I haven't seen segfaults in ages. Looks to be fixed on Node's side? Not sure if others share that experience or I somehow got lucky.

The flakey tests here were unrelated. HMR issues.

[danielweck]

Thanks @rschristian I'll check my Node / segfault status.