files ending in `_index.js` have `index` replaced with an empty string

[mylons]

in my config/importmap.rb i have a chunk like this:

pin_all_from "app/javascript/js", under: "js"
pin_all_from "app/javascript/packs", under: "packs"

and in app/javascript/packs these files:

$ ls -d app/javascript/packs/*index.js
app/javascript/packs/abi_qpcr_experiments_index.js     app/javascript/packs/cycling_conditions_index.js       app/javascript/packs/qc_ce_exo_experiment_index.js

and the resulting importmap in my html looks like:

"packs/abi_qpcr_experiments_": "/assets/packs/abi_qpcr_experiments_index-1924998a54634a9130705d836ab9821cc85e91ae5e24a764da11453f1e886a48.js",
"packs/cycling_conditions_": "/assets/packs/cycling_conditions_index-3a06c6dfab430b457fb88a0e248e36c32a69c586c71b40ebcc6fc4ecc7749f40.js",
"packs/qc_ce_exo_experiment_": "/assets/packs/qc_ce_exo_experiment_index-53c5205c7d54cc05a38d33e96af386a61d128c79fa8d59e2e734af303d790a7f.js",

is this expected behavior?

[mylons]

Ah, it does appear this is happening on purpose. I'm curious why? Should I rename my files?

importmap-rails/lib/importmap/map.rb

Line 144 in e0c1676

[ mapping.under, filename.to_s.remove(filename.extname).remove(/\/?index$/).presence ].compact.join("/")

Looking at the rest of the repo it's not obvious as to why a file ending in index should have that removed

[dhh]

It's happening to support that library/index.js can be referenced as library.js. But it's not intended that library_index.js is transformed. Please do explore a fix!

[Caleb-T-Owens]

Breaking down the regex, it's scanning for:

• \/? ← Matches one or zero / characters
• index ← Matches the word index
• $ ← Matches the end of a line

This is to try and match the following examples:

• index.js
• folder/index.js

But because it looks for 0 or 1 /, it also picks up super_index.js

I'm going to put together a PR updating this regex to /(:\/|^)index$/ which broken down is:

• (: ← Start non-capturing group
  • \/ ← Matches the / character
  • | ← OR operator
  • ^ ← Matches the start of the string
• ) ← Close group
• index ← Matches the word index
• $ ← Matches the end of a line

Which will still match

• index.js
• folder/index.js
  but specifically won't match super_index.js because we're now require either the string to start or the character / right before the word index