Clojurians Log v2

Something related hit my inbox the other day. While I doubt it's an easy fix it might help you on your way: https://github.com/facebook/metro/issues/104#issuecomment-1278243145

@olivergeorge Awesome, thanks for that pointer. Subscribing to that thread, and when the feature is straightened out with metro I’ll document whatever extra CLJS needs.

Can I ask you about your setup?

I was able to write a node.js script that merges cljs source maps into metro’s source map file. Maybe you can try it? https://github.com/shaunlebron/cljs-expo/blob/659505a1f832816f142f111178911294156755f2/expo/remap.js

I haven’t figured out how to insert this into Metro as a PR

and actually I just found this method: http://austinbirch.co.uk/clojurescript-react-native-bundling-release.html

@shaunlebron Oh, interesting, let me try this out.

did you use my script or austin’s?

@joshmiller ^

@shaunlebron Yours

(With modifications for my paths etc)

Great! Do you have any success for dev source maps? Just use chrome dev tools?

I haven’t tried for dev yet, I just use the errors I get in the Krell repl.

the Krell repl catches runtime errors?

(we’re using Expo)

Yes, it does.

Good to know, thank you!

Even turning Hermes off, our "mappings" key is empty, and they seemed to be moved to the x_facebook_sources extension:

{
  "version": 3,

  // STANDARD
  "sources": [ ... lots of filenames ... ],
  "sourcesContent": [ .. lots of file sources ... ],
  "names": [],   // <-- EMPTY
  "mappings": "" // <-- EMPTY

  // EXTENSIONS
  "x_facebook_sources": [
    null,
    [
      {
        "names": [ ... lots of names ],
        "mappings": "AAA;wBCyB,QD;..."
      }
    ],
    [
      {
        "names": [ ... lots of names ...],
        "mappings": "AAA;iBCiB;ECwB;..."
      }
    ],
    ... lots more ...
  ],
}

This script, modified a little bit for my different source file locations, turns out to have worked to get me ClojureScript-aware source maps. Thanks @shaunlebron!

Just a heads-up. I’m having some trouble using this method in a Hermes-bytecode build from Expo, internally produced with Metro somehow. This is the source map file e.g.:

{
  "version": 3,
  "sources": [],
  "names": [],
  "mappings": "A,4B,M,...",
  "x_facebook_sources": [],
  "x_hermes_function_offsets": {
    "0": [
      0,
      74130,
      74394,
      74423,
      74512,
      ...
    ]
  }
}

Hm, I haven’t tried with Hermes yet, interesting that it seems like it’s got some Hermes-specific info in there.