fix: Account for invalid identifiers (#198)

Author: AbhiPrasad

hook.js

@@ -254,19 +254,23 @@ async function processModule ({ srcUrl, context, parentGetSource, parentResolve,
         addSetter(name, setter, true)
       }
     } else {
+      const variableName = `$${n.replace(/[^a-zA-Z0-9_]/g, '_')}`
+      const objectKey = JSON.stringify(n)
+      const reExportedName = n === 'default' || NODE_MAJOR < 16 ? n : objectKey
+
       addSetter(n, `
-      let $${n}
+      let ${variableName}
       try {
-        $${n} = _.${n} = namespace.${n}
+        ${variableName} = _[${objectKey}] = namespace[${objectKey}]
       } catch (err) {
         if (!(err instanceof ReferenceError)) throw err
       }
-      export { $${n} as ${n} }
-      set.${n} = (v) => {
-        $${n} = v
+      export { ${variableName} as ${reExportedName} }
+      set[${objectKey}] = (v) => {
+        ${variableName} = v
         return true
       }
-      get.${n} = () => $${n}
+      get[${objectKey}] = () => ${variableName}
       `)
     }
   }

test/fixtures/invalid-identifier.js

@@ -0,0 +1,5 @@
+// These export identifiers are only supported in Node 16+
+exports['one.two'] = () => console.log('b')
+
+// See: https://github.com/nodejs/import-in-the-middle/issues/94
+exports['unsigned short'] = 'something'

test/fixtures/module-exports-cjs-shim.mjs

@@ -0,0 +1,7 @@
+// Regression test for https://github.com/nodejs/import-in-the-middle/issues/196
+
+export default function foo () {
+  // do nothing
+}
+
+export { foo as 'module.exports' }

test/hook/v16-fake-cjs-export.mjs

@@ -0,0 +1,4 @@
+import ui from '../fixtures/module-exports-cjs-shim.mjs'
+import { notStrictEqual } from 'assert'
+
+notStrictEqual(ui, undefined)

test/hook/v16-invalid-identifier.mjs

@@ -0,0 +1,5 @@
+import * as lib from '../fixtures/invalid-identifier.js'
+import { strictEqual } from 'assert'
+
+strictEqual(typeof lib['one.two'], 'function')
+strictEqual(typeof lib['unsigned short'], 'string')