doc: confusing support for extensionless ESM #30655

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1. azz commented on Nov 26, 2019

   

   azz

   on Nov 26, 2019

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   Ah I forgot about --es-module-specifier-resolution=node. Perhaps worth leaving a link to this flag in that area of the docs?
2. azz commented on Nov 26, 2019

   

   azz

   on Nov 26, 2019

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   It's documented at the very bottom of the page. Maybe update the example to say something like this? I feel like a lot of people are (like me!) going to run into this when switching to the native ESM loader.

    // my-app.js, part of the same example as above
    import './startup.js'; // Loaded as ES module because of package.json
   +
   +// Requires --es-module-specifier-resolution=node
   +import './startup'; // Loaded as ES module because of package.json
3. MylesBorins commented on Nov 27, 2019

   

   MylesBorins

   on Nov 27, 2019

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   Commented in the PR

   TL;DR
   Extensionless files, as documented, are different from extensionless specifiers.

   extensionless filepath and specifier

   • path /path/to/file
   • specifier import './file'

   filepath with extension and extensionless specifier

   • path /path/to/file.js
   • specifier import './file'
4. devsnek

   added

   esmIssues and PRs related to the ECMAScript Modules implementation.Issues and PRs related to the ECMAScript Modules implementation.

   experimentalIssues and PRs related to experimental features.Issues and PRs related to experimental features.

   on Dec 3, 2019
5. Alhadis commented on Dec 7, 2019

   

   Alhadis

   on Dec 7, 2019

   Last edited by Alhadis

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   I have an extensionless file (which is an executable) failing to be imported, despite package.json containing "type": "module":

   λ JG (master): cat ./test.mjs
   #!/usr/bin/env node
   
   import "./bin/list";
   λ JG (master): head bin/list
   #!/usr/bin/env node
   import {join, resolve} from "path";
   …
   
   λ JG (master): ./test.mjs
   (node:4311) ExperimentalWarning: The ESM module loader is experimental.
   internal/modules/run_main.js:50
       internalBinding('errors').triggerUncaughtException(
                                 ^
   
   TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension: /Users/john/Labs/JG/bin/list
       at Loader.resolve [as _resolve] (internal/modules/esm/default_resolve.js:114:13)
       at Loader.resolve (internal/modules/esm/loader.js:74:33)
       at Loader.getModuleJob (internal/modules/esm/loader.js:148:40)
       at ModuleWrap.<anonymous> (internal/modules/esm/module_job.js:41:40)
       at link (internal/modules/esm/module_job.js:40:36) {
     code: 'ERR_UNKNOWN_FILE_EXTENSION'
   }

   This happens both with static and dynamic imports.

   Current Node version: v13.2.0
6. MylesBorins

   closed this as completedin 3e5967bon Dec 18, 2019
7. BridgeAR

   added a commit that references this issue on Jan 3, 2020

   doc: clarify required flag for extensionless esm

   ...

   a386114
8. MylesBorins

   added a commit that references this issue on Jan 12, 2020

   doc: clarify required flag for extensionless esm

   ...

   c6b6e3f
9. BethGriggs

   added a commit that references this issue on Feb 6, 2020

   doc: clarify required flag for extensionless esm

   ...

   2cbb358