`no-unresolved`: support Bun module

[regseb]

The no-unresolved rule reports Node modules that don't exist. The rule could also report Bun modules (bun:bundle, bun:ffi, bun:jsc, bun:sqlite and bun:test) that don't exist.

• index.js

  import fs from "node:fs";
  import test from "bun:test";
  
  import foo from "node:idontexist";
  import bar from "bun:idontexist";

• package.json

  {
    "name": "testcase",
    "version": "1.0.0",
    "type": "module",
    "dependencies": {
      "eslint": "9.39.2",
      "eslint-plugin-import": "2.32.0"
    }
  }

• eslint.config.js

  import pluginImport from "eslint-plugin-import";
  
  export default [{
      plugins: { "import": pluginImport },
  
      rules: {
          "import/no-unresolved": "error",
      },
  }];

1. npm install
2. npx eslint

   • Actual:

     /home/regseb/testcase/index.js
       2:18  error  Unable to resolve path to module 'bun:test'         import/no-unresolved
       4:17  error  Unable to resolve path to module 'node:idontexist'  import/no-unresolved
       5:17  error  Unable to resolve path to module 'bun:idontexist'   import/no-unresolved
     
     ✖ 3 problems (3 errors, 0 warnings)
     

   • Expected:

     /home/regseb/testcase/index.js
       4:17  error  Unable to resolve path to module 'node:idontexist'  import/no-unresolved
       5:17  error  Unable to resolve path to module 'bun:idontexist'   import/no-unresolved
     
     ✖ 2 problems (2 errors, 0 warnings)
     

---

There could be an option to allow Bun imports:

runtimes (default: ["node"]): List of available runtimes ("node", "bun").

• Node.js: ["node"]
• Bun: ["node", "bun"]
• Browser: []

[ljharb]

This plugin generally assumes you're bundling, so "browser" isn't an important use case here - this specific rule doesn't resolve URLs.

The option you suggested is a reasonable way to support it, but I'm not sure it's worth the complexity given the very low usage of bun (or other node alternatives).