packages with main files that are not JavaScript are breaking acorn (v0.10.0 alpha)

[thescientist13]

Type of Change

• New Feature Request
• Documentation / Website
• Improvement / Suggestion
• Bug
• Other (please clarify below)

Summary

Was testing with the package simpledotcss which has a package.json#main file like this

{
  "main": "simple.css",
}

and was getting this error when running yarn develop

Started local development server at localhost:1984
dependency simpledotcss
packageEntryPointPath /Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/simpledotcss/simple.css

  SyntaxError: Unexpected token (2:0)
      at Parser.pp$4.raise (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:3014:15)
      at Parser.pp.unexpected (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:706:10)
      at Parser.pp$3.parseExprAtom (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2413:12)
      at Parser.pp$3.parseExprSubscripts (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2216:21)
      at Parser.pp$3.parseMaybeUnary (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2193:19)
      at Parser.pp$3.parseExprOps (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2128:21)
      at Parser.pp$3.parseMaybeConditional (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2111:21)
      at Parser.pp$3.parseMaybeAssign (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2079:21)
      at Parser.pp$3.parseExpression (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:2045:21)
      at Parser.pp$1.parseStatement (/Users/owenbuckley/Workspace/project-evergreen/repos/greenwood-getting-started/node_modules/acorn/dist/acorn.js:894:47)

Details

This makes sense given we are just assuming all packages in package.json are JavaScript based and so feeding a CSS file into acorn will break and also does not make sense for that getting put into an importMap.

Object.keys(packageJson.dependencies || {}).forEach(dependency => {
  ...

  walkModule(packageEntryModule, dependency);
  importMap[dependency] = `/node_modules/${dependency}/${entry}`;
  walkPackageJson(dependencyPackageJson);
});

Will just need to do some basic filtering of packages we put into the importMap.