fix: support npm modules with relative exports

node/npm_dependencies.ts

@@ -16,10 +16,18 @@ import { pathsBetween } from './utils/fs.js'
 
 const TYPESCRIPT_EXTENSIONS = new Set(['.ts', '.tsx', '.cts', '.ctsx', '.mts', '.mtsx'])
 
+const parseSpecifier = (specifier: string): { scope?: string; pkg: string; path?: string } => {
+  if (specifier.startsWith('@')) {
+    const [scope, pkg, path] = specifier.slice(1).split('/', 3)
+    return { scope, pkg, path }
+  }
+  const [pkg, path] = specifier.split('/', 2)
+  return { pkg, path }
+}
+
 const slugifyPackageName = (specifier: string) => {
-  if (!specifier.startsWith('@')) return specifier
-  const [scope, pkg] = specifier.split('/')
-  return `${scope.replace('@', '')}__${pkg}`
+  const { scope, pkg, path } = parseSpecifier(specifier)
+  return [scope, pkg, path?.replace(/\//g, '')].filter(Boolean).join('__')
 }
 
 /**
@@ -190,10 +198,16 @@ const getNPMSpecifiers = async ({ basePath, functions, importMap, environment, r
     // dependencies. Because we'll bundle all modules in a subsequent step,
     // any transitive dependencies will be handled then.
     if (isDirectDependency) {
-      npmSpecifiers.push({
-        specifier: packageName,
-        types: environment === 'development' ? await safelyDetectTypes(path.join(basePath, filePath)) : undefined,
-      })
+      const packJson = JSON.parse(await fs.readFile(path.join(basePath, filePath), { encoding: 'utf-8' }))
+
+      const subpaths = packJson.exports ? Object.keys(packJson.exports) : ['.']
+      // eslint-disable-next-line max-depth
+      for (const subpath of subpaths) {
+        npmSpecifiers.push({
+          specifier: path.join(packageName, subpath),
+          types: environment === 'development' ? await safelyDetectTypes(path.join(basePath, filePath)) : undefined,
+        })
+      }
     }
   }
 

node/npm_import_error.ts

@@ -4,6 +4,8 @@ class NPMImportError extends Error {
       `There was an error when loading the '${moduleName}' npm module. Support for npm modules in edge functions is an experimental feature. Refer to https://ntl.fyi/edge-functions-npm for more information.`,
     )
 
+    console.error(originalError)
+
     this.name = 'NPMImportError'
     this.stack = originalError.stack
 

test/fixtures/imports_npm_module/functions/func1.ts

@@ -2,6 +2,12 @@ import parent1 from 'parent-1'
 import parent3 from './lib/util.ts'
 import { echo, parent2 } from 'alias:helper'
 import { HTMLRewriter } from 'html-rewriter'
+import withSubpathIndex from "with-subpath"
+import withSubpathFoo from "with-subpath/foo"
+import assert from 'node:assert'
+
+assert(withSubpathIndex === "with-subpath/index")
+assert(withSubpathFoo === "with-subpath/foo")
 
 await Promise.resolve()