chore: code refactor

src/index.js

@@ -1,78 +1,94 @@
-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.object`).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: {
+module.exports = ({template, types}) => {
+  let pluginOptions
+  const visitor = {
     CallExpression: {
-      exit (path, state) {
+      exit (path) {
         // Not `Object.defineProperty`, skip
         if (!path.get('callee.object').node) {
           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 (isExportsModuleDeclaration(path)) {
+          const finder = new ExportFinder(path)
 
-        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 {
-              if (path.isExpressionStatement() && path.get('expression').isAssignmentExpression()) {
-                reminder.evaluateExpression(path)
-              }
-            }
-          })
+          if (finder.isOnlyDefaultExport()) {
+            const root = finder.getRootNode()
 
-          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)
-              ))
-            ])
-          }
-          if (state.opts.addDefaultProperty) {
-            program.pushContainer('body', [
-              types.expressionStatement(types.assignmentExpression(
-                '=',
-                types.memberExpression(types.memberExpression(types.identifier('module'), types.identifier('exports')), types.identifier('default')),
-                types.memberExpression(types.identifier('exports'), types.stringLiteral('default'), true)
-              ))
-            ])
+            // HACK: `program.node.body.push` instead of pushContainer(due doesn't work in Plugin.post)
+            root.node.body.push(template('module.exports = exports.default')())
+            if (pluginOptions.addDefaultProperty) {
+              root.node.body.push(template('module.exports.default = exports.default')())
+            }
           }
         }
       }
     }
   }
-})
+
+  return {
+    visitor: {
+      Program (path, state) {
+        // HACK: can't get plugin options in Plugin.post
+        pluginOptions = state.opts
+      }
+    },
+    post (fileMap) {
+      fileMap.path.traverse(visitor)
+    }
+  }
+}
+
+function isExportsModuleDeclaration (path) {
+  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(' ')
+
+  // TODO: support loose syntax `  exports.__esModule = true;`
+  return `${callee}${args}` === 'Object.defineProperty __esModule value:true'
+}
+
+class ExportFinder {
+  constructor (path) {
+    this.path = path
+    this.hasExportDefault = false
+    this.hasExportNamed = false
+  }
+  getRootNode () {
+    return this.path.parentPath.parentPath
+  }
+  isOnlyDefaultExport () {
+    this.getRootNode().get('body').forEach((path) => {
+      if (path.isVariableDeclaration()) {
+        this.findExport(path.get('declarations.0'), 'init')
+      } else {
+        if (path.isExpressionStatement() && path.get('expression').isAssignmentExpression()) {
+          this.findExport(path)
+        }
+      }
+    })
+    return this.hasExportDefault && !this.hasExportNamed
+  }
+  findExport (path, property = 'expression') {
+    // Not `exports.anything`, skip
+    if (!path.get(`${property}.left`).node || !path.get(`${property}.left.object`).node) {
+      return
+    }
+
+    const objectName = path.get(`${property}.left.object.name`).node
+    const propertyName = path.get(`${property}.left.property.name`).node
+    if (objectName === 'exports') {
+      if (propertyName === 'default') {
+        this.hasExportDefault = true
+      } else {
+        this.hasExportNamed = true
+      }
+    }
+    return null
+  }
+}