restructure classes transformer, fix class name inference - #1877

src/babel/transformation/transformers/es6/classes/index.js

@@ -0,0 +1,23 @@
+import LooseTransformer from "./loose";
+import VanillaTransformer from "./vanilla";
+import * as t from "../../../../types";
+import { bare } from "../../../helpers/name-method";
+
+export var visitor = {
+  ClassDeclaration(node) {
+    return t.variableDeclaration("let", [
+      t.variableDeclarator(node.id, t.toExpression(node))
+    ]);
+  },
+
+  ClassExpression(node, parent, scope, file) {
+    var inferred = bare(node, parent, scope);
+    if (inferred) return inferred;
+
+    if (file.isLoose("es6.classes")) {
+      return new LooseTransformer(this, file).run();
+    } else {
+      return new VanillaTransformer(this, file).run();
+    }
+  }
+};

src/babel/transformation/transformers/es6/classes/loose.js

@@ -0,0 +1,24 @@
+import VanillaTransformer from "./vanilla";
+import * as t from "../../../../types";
+
+export default class LooseClassTransformer extends VanillaTransformer {
+  constructor() {
+    super(...arguments);
+    this.isLoose = true;
+  }
+
+  _processMethod(node) {
+    if (!node.decorators) {
+      // use assignments instead of define properties for loose classes
+
+      var classRef = this.classRef;
+      if (!node.static) classRef = t.memberExpression(classRef, t.identifier("prototype"));
+      var methodName = t.memberExpression(classRef, node.key, node.computed || t.isLiteral(node.key));
+
+      var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
+      t.inheritsComments(expr, node);
+      this.body.push(expr);
+      return true;
+    }
+  }
+}

src/babel/transformation/transformers/es6/classes/vanilla.js

@@ -1,27 +1,15 @@
-import type NodePath from "../../../traversal/path";
-import type File from "../../file";
-import memoiseDecorators from "../../helpers/memoise-decorators";
-import ReplaceSupers from "../../helpers/replace-supers";
-import * as nameMethod from "../../helpers/name-method";
-import * as defineMap from "../../helpers/define-map";
-import * as messages from "../../../messages";
-import * as util from  "../../../util";
-import * as t from "../../../types";
+import type NodePath from "../../../../traversal/path";
+import type File from "../../../file";
+import memoiseDecorators from "../../../helpers/memoise-decorators";
+import ReplaceSupers from "../../../helpers/replace-supers";
+import * as nameMethod from "../../../helpers/name-method";
+import * as defineMap from "../../../helpers/define-map";
+import * as messages from "../../../../messages";
+import * as util from  "../../../../util";
+import * as t from "../../../../types";
 
 const PROPERTY_COLLISION_METHOD_NAME = "__initializeProperties";
 
-export var visitor = {
-  ClassDeclaration(node) {
-    return t.variableDeclaration("let", [
-      t.variableDeclarator(node.id, t.toExpression(node))
-    ]);
-  },
-
-  ClassExpression(node, parent, scope, file) {
-    return new ClassTransformer(this, file).run();
-  }
-};
-
 var collectPropertyReferencesVisitor = {
   Identifier: {
     enter(node, parent, scope, state) {
@@ -83,7 +71,7 @@ var verifyConstructorVisitor = {
   }
 };
 
-class ClassTransformer {
+export default class ClassTransformer {
 
   /**
    * Description
@@ -96,11 +84,7 @@ class ClassTransformer {
     this.path   = path;
     this.file   = file;
 
-    this.hasInstanceDescriptors = false;
-    this.hasStaticDescriptors   = false;
-
-    this.instanceMutatorMap = {};
-    this.staticMutatorMap   = {};
+    this.clearDescriptors();
 
     this.instancePropBody = [];
     this.instancePropRefs = {};
@@ -108,15 +92,21 @@ class ClassTransformer {
     this.body             = [];
 
     this.pushedConstructor = false;
-    this.hasConstructor    = false;
+    this.pushedInherits    = false;
     this.hasDecorators     = false;
-    this.className         = this.node.id;
-    this.classRef          = this.node.id || this.scope.generateUidIdentifier("class");
+    this.isLoose           = false;
+
+    // class id
+    this.className = this.node.id;
+
+    // this is the name of the binding that will **always** reference the class we've constructed
+    this.classRef = this.node.id || this.scope.generateUidIdentifier("class");
+
+    // this is a direct reference to the class we're building, class decorators can shadow the classRef
+    this.directRef = null;
 
     this.superName = this.node.superClass || t.identifier("Function");
     this.hasSuper  = !!this.node.superClass;
-
-    this.isLoose = file.isLoose("es6.classes");
   }
 
   /**
@@ -137,15 +127,7 @@ class ClassTransformer {
     //
 
     var constructorBody = this.constructorBody = t.blockStatement([]);
-    var constructor;
-
-    if (this.className) {
-      constructor = t.functionDeclaration(this.className, [], constructorBody);
-    } else {
-      constructor = t.functionExpression(null, [], constructorBody);
-    }
-
-    this.constructor = constructor;
+    var constructor = this.constructor = this.buildConstructor();
 
     //
 
@@ -160,19 +142,15 @@ class ClassTransformer {
       closureParams.push(superName);
 
       this.superName = superName;
-      body.push(t.expressionStatement(t.callExpression(file.addHelper("inherits"), [classRef, superName])));
     }
 
     //
     var decorators = this.node.decorators;
     if (decorators) {
-      // create a class reference to use later on
-      this.classRef = this.scope.generateUidIdentifier(classRef);
-
       // this is so super calls and the decorators have access to the raw function
-      body.push(t.variableDeclaration("var", [
-        t.variableDeclarator(this.classRef, classRef)
-      ]));
+      this.directRef = this.scope.generateUidIdentifier(this.classRef);
+    } else {
+      this.directRef = this.classRef;
     }
 
     //
@@ -181,26 +159,11 @@ class ClassTransformer {
     // make sure this class isn't directly called
     constructorBody.body.unshift(t.expressionStatement(t.callExpression(file.addHelper("class-call-check"), [
       t.thisExpression(),
-      this.classRef
+      this.directRef
     ])));
 
     //
-
-    if (decorators) {
-      // reverse the decorators so we execute them in the right order
-      decorators = decorators.reverse();
-
-      for (var i = 0; i < decorators.length; i++) {
-        var decorator = decorators[i];
-
-        var decoratorNode = util.template("class-decorator", {
-          DECORATOR: decorator.expression,
-          CLASS_REF: classRef
-        }, true);
-        decoratorNode.expression._ignoreModulesRemap = true;
-        body.push(decoratorNode);
-      }
-    }
+    this.pushDecorators();
 
     body = body.concat(this.staticPropBody);
 
@@ -210,8 +173,7 @@ class ClassTransformer {
     }
 
     //
-
-    body.push(t.returnStatement(classRef));
+    body.push(t.returnStatement(this.classRef));
 
     return t.callExpression(
       t.functionExpression(null, closureParams, t.blockStatement(body)),
@@ -219,6 +181,14 @@ class ClassTransformer {
     );
   }
 
+  /**
+   * Description
+   */
+
+  buildConstructor() {
+    return t.functionDeclaration(this.classRef, [], this.constructorBody);
+  }
+
   /**
    * Description
    */
@@ -261,7 +231,7 @@ class ClassTransformer {
     if (this.hasSuper) {
       constructor = util.template("class-derived-default-constructor");
     } else {
-      constructor = t.functionExpression(null, [], t.blockStatement());
+      constructor = t.functionExpression(null, [], t.blockStatement([]));
     }
 
     this.path.get("body").unshiftContainer("body", t.methodDefinition(
@@ -277,10 +247,17 @@ class ClassTransformer {
 
   buildBody() {
     this.constructorMeMaybe();
+    this.pushBody();
+    this.placePropertyInitializers();
+    this.pushDescriptors();
+  }
 
-    var constructorBody = this.constructorBody;
-    var classBodyPaths  = this.path.get("body.body");
-    var body            = this.body;
+  /**
+   * Description
+   */
+
+  pushBody() {
+    var classBodyPaths = this.path.get("body.body");
 
     for (var path of (classBodyPaths: Array)) {
       var node = path.node;
@@ -296,7 +273,7 @@ class ClassTransformer {
         var replaceSupers = new ReplaceSupers({
           methodPath: path,
           methodNode: node,
-          objectRef:  this.classRef,
+          objectRef:  this.directRef,
           superRef:   this.superName,
           isStatic:   node.static,
           isLoose:    this.isLoose,
@@ -315,16 +292,28 @@ class ClassTransformer {
         this.pushProperty(node, path);
       }
     }
+  }
 
-    //
-    this.placePropertyInitializers();
+  /**
+   * Description
+   */
 
-    //
-    if (this.userConstructor) {
-      constructorBody.body = constructorBody.body.concat(this.userConstructor.body.body);
-      t.inherits(this.constructor, this.userConstructor);
-      t.inherits(this.constructorBody, this.userConstructor.body);
-    }
+  clearDescriptors() {
+    this.hasInstanceDescriptors = false;
+    this.hasStaticDescriptors   = false;
+
+    this.instanceMutatorMap = {};
+    this.staticMutatorMap   = {};
+  }
+
+  /**
+   * Description
+   */
+
+  pushDescriptors() {
+    this.pushInherits();
+
+    var body = this.body;
 
     var instanceProps;
     var staticProps;
@@ -372,8 +361,14 @@ class ClassTransformer {
         t.callExpression(this.file.addHelper(classHelper), args)
       ));
     }
+
+    this.clearDescriptors();
   }
 
+  /**
+   * Description
+   */
+
   buildObjectAssignment(id) {
     return t.variableDeclaration("var", [
       t.variableDeclarator(id, t.objectExpression([]))
@@ -406,11 +401,7 @@ class ClassTransformer {
       }
     } else {
       if (this.hasSuper) {
-        if (this.hasConstructor) {
-          this.bareSuper.insertAfter(body);
-        } else {
-          this.constructorBody.body = this.constructorBody.body.concat(body);
-        }
+        this.bareSuper.insertAfter(body);
       } else {
         this.constructorBody.body = body.concat(this.constructorBody.body);
       }
@@ -431,7 +422,7 @@ class ClassTransformer {
     }
 
     return false;
-   }
+  }
 
   /**
    * Description
@@ -465,24 +456,16 @@ class ClassTransformer {
 
     if (node.kind === "method") {
       nameMethod.property(node, this.file, path ? path.get("value").scope : this.scope);
-
-      if (this.isLoose && !node.decorators) {
-        // use assignments instead of define properties for loose classes
-
-        var classRef = this.classRef;
-        if (!node.static) classRef = t.memberExpression(classRef, t.identifier("prototype"));
-        var methodName = t.memberExpression(classRef, node.key, node.computed || t.isLiteral(node.key));
-
-        var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
-        t.inheritsComments(expr, node);
-        this.body.push(expr);
-        return;
-      }
+      if (this._processMethod(node)) return;
     }
 
     this.pushToMap(node);
   }
 
+  _processMethod() {
+    return false;
+  }
+
   /**
    * Description
    */
@@ -549,13 +532,16 @@ class ClassTransformer {
       fnPath.scope.rename(this.classRef.name);
     }
 
-    var construct = this.constructor;
-    var fn        = method.value;
+    var constructorBody = this.constructorBody;
+    var construct       = this.constructor;
+    var fn              = method.value;
 
     this.userConstructorPath = fnPath;
-    this.userConstructor     = fn;
-    this.hasConstructor      = true;
 
+    constructorBody.body = constructorBody.body.concat(fn.body.body);
+    t.inherits(constructorBody, fn.body);
+
+    t.inherits(construct, fn);
     t.inheritsComments(construct, method);
 
     construct._ignoreUserWhitespace = true;
@@ -564,21 +550,59 @@ class ClassTransformer {
     t.inherits(construct.body, fn.body);
 
     // push constructor to body
-    if (!this.pushedConstructor) {
-      this.pushedConstructor = true;
+    this._pushConstructor();
+  }
 
-      if (this.className) {
-        this.body.push(construct);
-      } else {
-        // infer class name if this is a nameless class expression
-        this.constructor = nameMethod.bare(construct, this.parent, this.scope) || construct;
+  _pushConstructor() {
+    if (this.pushedConstructor) return;
+    this.pushedConstructor = true;
 
-        this.body.push(t.variableDeclaration("var", [
-          t.variableDeclarator(classRef, constructor)
-        ]));
+    // we haven't pushed any descriptors yet
+    if (this.hasInstanceDescriptors || this.hasStaticDescriptors) {
+      this.pushDescriptors();
+    }
 
-        t.inheritsComments(this.body[0], this.node);
-      }
+    this.body.push(this.constructor);
+
+    this.pushInherits();
+  }
+
+  /**
+   * Push inherits helper to body.
+   */
+
+  pushInherits() {
+    if (!this.hasSuper || this.pushedInherits) return;
+
+    this.pushedInherits = true;
+    this.body.push(t.expressionStatement(t.callExpression(
+      this.file.addHelper("inherits"),
+      [this.classRef, this.superName]
+    )));
+  }
+
+  /**
+   * Push decorators to body.
+   */
+
+  pushDecorators() {
+    var decorators = this.node.decorators;
+    if (!decorators) return;
+
+    this.body.push(t.variableDeclaration("var", [
+      t.variableDeclarator(this.directRef, this.classRef)
+    ]));
+
+    // reverse the decorators so we execute them in the right order
+    decorators = decorators.reverse();
+
+    for (var decorator of (decorators: Array)) {
+      var decoratorNode = util.template("class-decorator", {
+        DECORATOR: decorator.expression,
+        CLASS_REF: this.classRef
+      }, true);
+      decoratorNode.expression._ignoreModulesRemap = true;
+      this.body.push(decoratorNode);
     }
   }
 }

test/core/fixtures/transformation/es6.classes-loose/constructor-order/expected.js

@@ -11,7 +11,6 @@ var x = (function () {
     4;
     5;
     6;
-
     babelHelpers.classCallCheck(this, x);
   }
 

test/core/fixtures/transformation/es6.classes/statement/expected.js

@@ -6,26 +6,22 @@ var BaseView = function BaseView() {
   this.autoRender = true;
 };
 
-var BaseView = (function () {
-  var _class = function BaseView() {
-    babelHelpers.classCallCheck(this, _class);
+var BaseView = function BaseView() {
+  babelHelpers.classCallCheck(this, BaseView);
 
-    this.autoRender = true;
-  };
-
-  return _class;
-})();
+  this.autoRender = true;
+};
 
 var BaseView = (function () {
-  var _class2 = function BaseView() {
-    babelHelpers.classCallCheck(this, _class2);
-  };
+  function BaseView() {
+    babelHelpers.classCallCheck(this, BaseView);
+  }
 
-  babelHelpers.createClass(_class2, [{
+  babelHelpers.createClass(BaseView, [{
     key: "foo",
     value: function foo() {
       this.autoRender = true;
     }
   }]);
-  return _class2;
+  return BaseView;
 })();

test/core/fixtures/transformation/es6.classes/super-class-anonymous/expected.js

@@ -9,9 +9,9 @@ var TestEmpty = (function (_ref) {
   babelHelpers.inherits(TestEmpty, _ref);
   return TestEmpty;
 })((function () {
-  var _class = function _class() {
+  function _class() {
     babelHelpers.classCallCheck(this, _class);
-  };
+  }
 
   return _class;
 })());
@@ -25,9 +25,9 @@ var TestConstructorOnly = (function (_ref2) {
   babelHelpers.inherits(TestConstructorOnly, _ref2);
   return TestConstructorOnly;
 })((function () {
-  var _class2 = function _class2() {
+  function _class2() {
     babelHelpers.classCallCheck(this, _class2);
-  };
+  }
 
   return _class2;
 })());
@@ -41,9 +41,9 @@ var TestMethodOnly = (function (_ref3) {
   babelHelpers.inherits(TestMethodOnly, _ref3);
   return TestMethodOnly;
 })((function () {
-  var _class3 = function _class3() {
+  function _class3() {
     babelHelpers.classCallCheck(this, _class3);
-  };
+  }
 
   babelHelpers.createClass(_class3, [{
     key: "method",
@@ -61,9 +61,9 @@ var TestConstructorAndMethod = (function (_ref4) {
   babelHelpers.inherits(TestConstructorAndMethod, _ref4);
   return TestConstructorAndMethod;
 })((function () {
-  var _class4 = function _class4() {
+  function _class4() {
     babelHelpers.classCallCheck(this, _class4);
-  };
+  }
 
   babelHelpers.createClass(_class4, [{
     key: "method",
@@ -81,9 +81,9 @@ var TestMultipleMethods = (function (_ref5) {
   babelHelpers.inherits(TestMultipleMethods, _ref5);
   return TestMultipleMethods;
 })((function () {
-  var _class5 = function _class5() {
+  function _class5() {
     babelHelpers.classCallCheck(this, _class5);
-  };
+  }
 
   babelHelpers.createClass(_class5, [{
     key: "m1",

test/core/fixtures/transformation/es6.modules-amd/exports-default/expected.js

@@ -9,13 +9,9 @@ define(["exports", "module"], function (exports, module) {
 
   module.exports = function () {};
 
-  var _default = (function () {
-    var _class = function _default() {
-      babelHelpers.classCallCheck(this, _class);
-    };
-
-    return _class;
-  })();
+  var _default = function _default() {
+    babelHelpers.classCallCheck(this, _default);
+  };
 
   module.exports = _default;
 

test/core/fixtures/transformation/es6.modules-common/exports-default/expected.js

@@ -11,13 +11,9 @@ exports["default"] = foo;
 
 exports["default"] = function () {};
 
-var _default = (function () {
-  var _class = function _default() {
-    babelHelpers.classCallCheck(this, _class);
-  };
-
-  return _class;
-})();
+var _default = function _default() {
+  babelHelpers.classCallCheck(this, _default);
+};
 
 exports["default"] = _default;
 

test/core/fixtures/transformation/es6.modules-ignore/exports-default/expected.js

@@ -2,13 +2,9 @@
 
 function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
 
-var _default = (function () {
-  var _class = function _default() {
-    _classCallCheck(this, _class);
-  };
-
-  return _class;
-})();
+var _default = function _default() {
+  _classCallCheck(this, _default);
+};
 
 function foo() {}
 

test/core/fixtures/transformation/es6.modules-system/exports-default/expected.js

@@ -22,13 +22,9 @@ System.register([], function (_export) {
 
       _export("default", function () {});
 
-      _default = (function () {
-        var _class = function _default() {
-          _classCallCheck(this, _class);
-        };
-
-        return _class;
-      })();
+      _default = function _default() {
+        _classCallCheck(this, _default);
+      };
 
       _export("default", _default);
 
@@ -43,4 +39,4 @@ System.register([], function (_export) {
       })());
     }
   };
-});
+});

test/core/fixtures/transformation/es6.modules-umd/exports-default/expected.js

@@ -21,13 +21,9 @@
 
   module.exports = function () {};
 
-  var _default = (function () {
-    var _class = function _default() {
-      babelHelpers.classCallCheck(this, _class);
-    };
-
-    return _class;
-  })();
+  var _default = function _default() {
+    babelHelpers.classCallCheck(this, _default);
+  };
 
   module.exports = _default;
 

test/core/fixtures/transformation/es7.decorators/class-super/expected.js

@@ -14,14 +14,14 @@ var Foo = (function (_Bar) {
 })(Bar);
 
 var Foo2 = (function (_Bar2) {
-  var _class = function Foo2() {
-    babelHelpers.classCallCheck(this, _class2);
+  function Foo2() {
+    babelHelpers.classCallCheck(this, _Foo2);
 
-    babelHelpers.get(Object.getPrototypeOf(_class2.prototype), "constructor", this).call(this);
-  };
+    babelHelpers.get(Object.getPrototypeOf(_Foo2.prototype), "constructor", this).call(this);
+  }
 
-  babelHelpers.inherits(_class, _Bar2);
-  var _class2 = _class;
-  _class = bar(_class) || _class;
-  return _class;
-})(Bar);
+  babelHelpers.inherits(Foo2, _Bar2);
+  var _Foo2 = Foo2;
+  Foo2 = bar(Foo2) || Foo2;
+  return Foo2;
+})(Bar);