fix: undefined exports issues

BREAKING CHANGE: If `__esModule` exists and `export default` only exists, add `module.exports`.
59naga · Jun 25, 2018 · c4aa1b0 · c4aa1b0
1 parent 3487ac1
commit c4aa1b0
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Showing 2 changed files with 65 additions and 24 deletions.
diff --git a/src/index.js b/src/index.js
@@ -1,39 +1,68 @@
+class AssignmentReminder {
+  constructor () {
+    this.hasExportDefault = false
+    this.hasExportNamed = false
+  }
+  evaluateExpression (path, property = 'expression') {
+    // Not `exports.anything`, skip
+    if (!path.get(`${property}.left`).node || !path.get(`${property}.left.property`).node) {
+      return
+    }
+
+    const objectName = path.get(`${property}.left.object.name`).node
+    const propertyName = path.get(`${property}.left.property.name`).node
+    const name = `${objectName}.${propertyName}`
+    if (name === 'exports.default') {
+      this.hasExportDefault = true
+    } else if (objectName === 'exports') {
+      this.hasExportNamed = true
+    }
+  }
+}
+
 module.exports = ({types}) => ({
   visitor: {
-    Program: {
+    CallExpression: {
       exit (path) {
-        if (path.BABEL_PLUGIN_ADD_MODULE_EXPORTS) {
+        // Not `Object.defineProperty`, skip
+        if (path.get('callee.name').node) {
           return
         }
 
-        let hasExportDefault = false
-        let hasExportNamed = false
-        path.get('body').forEach((path) => {
-          if (path.isExportDefaultDeclaration()) {
-            hasExportDefault = true
-            return
+        const callee = `${path.get('callee.object.name').node}.${path.get('callee.property.name').node}`
+        const args = path.get('arguments').map(path => {
+          if (path.isStringLiteral()) {
+            return path.get('value').node
+          }
+          if (path.get('properties').length) {
+            return `${path.get('properties.0.key.name').node}:${path.get('properties.0.value.value').node}`
           }
+        }).join(' ')
 
-          if (path.isExportNamedDeclaration()) {
-            if (path.node.specifiers.length === 1 && path.node.specifiers[0].exported.name === 'default') {
-              hasExportDefault = true
+        const isLegacyModule = `${callee}${args}` === 'Object.defineProperty __esModule value:true'
+        if (isLegacyModule) {
+          const reminder = new AssignmentReminder()
+          const program = path.parentPath.parentPath
+          program.get('body').forEach((path) => {
+            if (path.isVariableDeclaration()) {
+              reminder.evaluateExpression(path.get('declarations.0'), 'init')
             } else {
-              hasExportNamed = true
+              if (path.isExpressionStatement() && path.get('expression').isAssignmentExpression()) {
+                reminder.evaluateExpression(path)
+              }
             }
-          }
-        })
+          })
 
-        if (hasExportDefault && !hasExportNamed) {
-          path.pushContainer('body', [
-            types.expressionStatement(types.assignmentExpression(
-              '=',
-              types.memberExpression(types.identifier('module'), types.identifier('exports')),
-              types.memberExpression(types.identifier('exports'), types.stringLiteral('default'), true)
-            ))
-          ])
+          if (reminder.hasExportDefault && !reminder.hasExportNamed) {
+            program.pushContainer('body', [
+              types.expressionStatement(types.assignmentExpression(
+                '=',
+                types.memberExpression(types.identifier('module'), types.identifier('exports')),
+                types.memberExpression(types.identifier('exports'), types.stringLiteral('default'), true)
+              ))
+            ])
+          }
         }
-
-        path.BABEL_PLUGIN_ADD_MODULE_EXPORTS = true
       }
     }
   }

diff --git a/test/index.js b/test/index.js
@@ -1,4 +1,5 @@
 import assert from 'assert'
+import {transform as babelTransform} from 'babel-core'
 import { testPlugin, equal } from './helpers'
 import testCases from './spec'
 
@@ -11,6 +12,17 @@ describe('babel-plugin-add-module-exports', () => {
       assert(module.default === 'default-entry')
     }))
 
+  it('should not handle an pure esmodule', () => {
+    const code = `export default 'default-entry';`
+    const result = babelTransform(code, {
+      presets: [['env', {modules: false}]],
+      plugins: [
+        './src/index.js'
+      ]
+    })
+    assert(code === result.code)
+  })
+
   it('plugin should export to module.exports(#31)', () => {
     const plugin = require('../src')
     assert(typeof plugin === 'function')