Creates lessc Makefile function to DRY up Less commands

[shaneriley]

Description: What does this PR achieve? [feature|hotfix|refactor]

Closes #1879

Technical: What should be noted about the implementation?

Refactoring to a function eliminated the default terminal output. Added an echo to note which file was being processed.

Testing: Steps for reviewer to reproduce / verify this PR fixes the problem?

Run docker-compose exec web make css

Evidence: If this PR touches UI, please post evidence (screenshot) of it behaving correctly:

N/A

[brad2014]

If you wanted to do the old-fashioned make dependency approach, it might look something like this...

CSS_PAGES  = admin book edit form home lists plain subject user book-widget design dev 

.PHONY: css 
css: $(patsubst %,$(BUILD)/page-%.css,$(CSS_PAGES)) $(BUILD)/js-all.css

$(BUILD)/%.css : static/css/%.less $(BUILD)
  @echo Compressing $<
  lessc -x $< $@

$(BUILD) :
  mkdir -p $@

[jdlrobson]

This is cool, but wondering what it would take to move these into package.json ?

[shaneriley]

We can go the watcher route instead, which would be great considering you don't have to run make every time you change styles, but it will require some rewriting and reorganization of the Less files. Adding https://www.npmjs.com/package/less-watch-compiler, for example, can allow us to specify the source and destination directories, but it will blindly compile each file individually which will lead to errors. There are a lot of Less files that assume previous Less files have been compiled in before it, and use variables that aren't instantiated in that file.

I'm not sure if we can have a similar setup with existing Less watchers, but when I use Sass I set up Chokidar to ignore files prepended with an underscore to get around that. I'll do some research and see if there's a similar option.

[jdlrobson]

I'm hoping to move this into webpack and drop the lessc compiler altogether.

See #1936 and #1123
I've also setup a board to track work for this project of JS modernization.
https://github.com/internetarchive/openlibrary/projects/10?add_cards_query=is%3Aopen

[mekarpeles]

It looks like with #2003 this can be closed

[shaneriley]

It looks like with #2003 this can be closed

👍 on it being irrelevant once #2003 is merged.