Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

Helmet behaves strangely when rendering is asynchronous

See original GitHub issue

I was seeing some odd behavior with meta tags in the head of the static pages in my project. I created a new basic template, added a <Head><title> This is About </title></Head> to the About container, and <Head><title> This is Home </title></Head> to the Home container, and ran yarn build.

The About-title ended up in the index.html file and the Home-title was nowhere to be seen.

I looked into it a bit, and I think the async renderToString is the culprit. It works as intended if I just remove the await keyword.

It looks like Helmet doesn’t work all that well if the rendering is asynchronous. I dare not create a PR making it synchronous, because I’m sure it has some other use case I’m not aware of.

Issue Analytics

State:
Created 6 years ago
Comments:7 (6 by maintainers)

Top GitHub Comments

1reaction

xogenycommented, Nov 13, 2017

Why is it necessary to change renderToHtml to be synchronous? If people want it to be synchronous, just don’t have it return a Promise.

The ability to have it be async is quite important. For example, I’m planning in integration mathjax-node-page so that my equations get converted to <svg> elements during site compilation. The conversion is synchronous, so making renderToHtml will break everything. I can imagine plenty of other scenarios as well.

If getRoutes can be async, why can’t renderToHtml?

1reaction

tannerlinsleycommented, Nov 13, 2017

Yes, we should most definitely change the renderToHtml method to be synchronous. This will be a breaking change mostly because of syntax. So we’ll save it for the next breaking change batch.