v0.16.6 - failed to start esbuild if any ESM loader was present

[koshic]

Install esbuild and run it with any ESM loader. In this example, I use 'bin' script directly to avoid package manager related things. Loader is empty (which is valid according to specs - just no resolve / load hooks will be added to the chain):

node --loader 'data:text/javascript,//' ./node_modules/esbuild/bin/esbuild

(node:1874) ExperimentalWarning: Custom ESM Loaders is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
node:internal/errors:484
    ErrorCaptureStackTrace(err);
    ^

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension "" for <some my machine path>/node_modules/esbuild/bin/esbuild
    at new NodeError (node:internal/errors:393:5)
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:75:9)
    at defaultGetFormat (node:internal/modules/esm/get_format:114:38)
    at defaultLoad (node:internal/modules/esm/load:81:20)
    at nextLoad (node:internal/modules/esm/loader:161:28)
    at ESMLoader.load (node:internal/modules/esm/loader:594:26)
    at ESMLoader.moduleProvider (node:internal/modules/esm/loader:446:22)
    at new ModuleJob (node:internal/modules/esm/module_job:64:26)
    at #createModuleJob (node:internal/modules/esm/loader:469:17)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:423:34) {
  code: 'ERR_UNKNOWN_FILE_EXTENSION'
}

Node.js v19.2.0

From my understanding, the issue is related to the script extension (== no extension). It's OK for pure commonjs setup, but when we ask node to use loaders flow by --loader flag, node will execute defaultResolve / defaultLoad hooks for every incoming file. Next, defaultResolve can't handle files without extension, and return 'format: undefined' - which leads to fail inside defaultLoad.

'format: commonjs' at resolve stage (in my PoC I just test incoming url with '*/bin/esbuild' inside the hook) solves the issue - as per docs, it will activate some kind of CJS fallback. But it looks like a dirty hack )

So, proposed solution - to add .js (or even .cjs) extension to the 'bin' script (and change package.json too).

My use case (== 'why do you use loader here?') is simple - loader (simple ts transpiler) added for every 'yarn xxx' via NODE_OPTIONS yarn configuration, which is very useful for TS monorepo (no need to compile eslint / jest configs, etc.).

ps checked with node 18 too.

[evanw]

It would be incorrect to add a JavaScript file extension to node_modules/esbuild/bin/esbuild because it's not JavaScript:

$ file node_modules/esbuild/bin/esbuild 
node_modules/esbuild/bin/esbuild: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, Go BuildID=iWVTDvMSaaeGwO_F8vaK/NFjtd-nUjLjQTPHhjwyu/z49zWfHmA6HcCqcPWWnL/unMqBi8H25Gzyhp9Paku, stripped

The underlying problem is that you're trying to run a binary executable through node. Don't do that. Just run it directly.

Edit: Sorry, I missed that you're using Yarn. My comment above was for people who install esbuild with a non-Yarn package manager. The install script overwrites the JavaScript file you're referencing with a binary executable for speed, but it doesn't do this for Yarn because Yarn has bugs regarding binary executables as bin scripts: yarnpkg/berry#882.

In any case, I'm not going to change the name of the esbuild command to esbuild.js. You are welcome to work around this problem in whatever way works best for you.

[koshic]

Thx, but why do you need to change 'esbuild' command? Just change filename and reference in package.json:

Especially if you are using 'full' form of 'bin' entry and specifying exact command name (== "esbuild") instead of "bin: ./bin/esbuild".

Or it means that you should change binary name for non-yarn envs, right?