Agile Web Development with Rails 7: Reloading assets in development mode

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Hi all,

currently I wonder how the Tailwind colours work (or don’t work).

For example, in app/views/layouts/application.html.erb I have this:

<header class="bg-green-600">

and, yes, the header part is indeed green.

But when I change it to, for example

<header class="bg-sky-600">

and reload the page, the background is white. Why is that?
I assumed the examples from the Tailwind docs at https://tailwindcss.com/docs/background-color, can be used elsewhere (read: my local app).
And while that’s true from some of the named colours, it is not for others.
‘bg-blue-700’ yields a strong blue, ‘bg-orange-500’ & ‘bg-fuchsia-600’ is white. A ‘one-off’ colour is also displayed white (or ignored?).

After running

bin/rails assets precompile

these colours are displayed in the browser.
What causes this behaviour? Can it be changed, to get all the colours Tailwind has in store (e.g. also the ‘one-off’ colours such as class="bg-[#50d71e]" (also from the Tailwind docs)?

Cheers
Stephan

2

Short answer: stop your server, run rails assets:clobber, and restart your server.

I guess the question I have to ask: why did you run bin/rails assets:precompile? What that does is to create a static snapshot of your tailwind classes and put the results into your public/assets directory. If that directory exists when the server is started, puma will serve those files and never forward the request to rails at all. The end result is any tailwind classes you try to make use of will be ignored unless they are in that static snapshot.

1 Like
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Thanks for your answer.

Why I ran assets:precompile: I’m a tester, I try things and see what happens.

I also tried asters:clobber, but still some colours are displayed, others aren’t.

I finally added some CSS classes to the application CSS file and used the colours I defined there.

That doesn’t explain (to me) why the colours shown in the Tailwind docs aren’t displayed.

I’ll try with a brand new Rails app tomorrow morning.

4

What I did to reproduce the problem:

rails new play --css tailwind
cd play
rails generate scaffold say hello
bin/dev

Adding bg-green-600 to app/views/say/hello.html.erb worked at this point.

Stopping the server, running rails assets:precompile, restarting the server, and then changing the color to bg-sky-600 did not work - the background was white – this matched what you reported.

Stopping the server, running rails assets:clobber, and restarting the server, and I can see the new color. I can then change the color to bg-red-600 and see the results of my change.

1 Like
5

Aha, now I see were I went wrong: While, I usually default to using Foreman, I used bin/rails server, which doesn’t watch for Tailwind related changes, while the Procfile.dev does.

It’s nice that bin/dev even installs foreman if it isn’t already there.