SSR outputs <undefined></undefined> node

[ciampo]

Do you want to request a feature or report a bug?
Bug

What is the current behaviour?

When enabling SSR, the output is a <undefined></undefined> node, instead of the contents of the page

If the current behaviour is a bug, please provide the steps to reproduce.

1. Follow this gist to use latest preact cli, and update preact dependencies to latest version: https://gist.github.com/developit/f1a3425ded9b52206c372b6c6b54ddcb

2. Add a prerender-urls.json file in the root project folder and add this content:

[
  {
    "url": "/",
    "title": "Homepage"
  }
]

3. run npm run build

4. notice how the file build/index.html has a <undefined></undefined> HTML node instead of the SSRs page

What is the expected behaviour?

The SSR'd HTML file should include the page contents.

If this is a feature request, what is motivation or use case for changing the behaviour?

N/A

Please mention other relevant information.

• Node version 12.3.1
• npm version 6.9.0
• Operating system MacOS 10.14.5
• CLI version 3.0.0-rc.2
• Browser N/A

[ForsakenHarmony]

Do you have preact-compat installed? if so please remove it

[ciampo]

Good catch, I did have it installed.

Although I removed preact-compat from package.json, re-installed dependencies, and I am still having the same problem.

Can you reproduce it too?

[evont]

maybe you should try upgrading preact-render-to-string to 5.02

[ForsakenHarmony]

yeah I forgot about that part thanks @evont

We should make it more obvious though

/cc @developit

[ciampo]

Thank you @evont, that fixed it!

@ForsakenHarmony Yeah it'd be a good idea to update the gist

[developit]

Gist updated. Might be neat for us to add a check to the CLI that verifies known good versions.

[reznord]

This is fixed in the latest versions of CLI.