make super behaviour more spec compliant - fixes #32

lib/6to5/templates/class-super-constructor-call.js

@@ -0,0 +1,2 @@
+SUPER_NAME.call(this, arguments);
+

lib/6to5/transformers/classes.js

@@ -71,18 +71,22 @@ var buildClass = function (node, generateUid) {
 
 var buildClassBody = function (body, className, superName, node) {
   var instanceMutatorMap = {};
-  var staticMutatorMap = {};
+  var staticMutatorMap   = {};
+  var hasConstructor     = false;
 
+  var construct = body[0];
   var classBody = node.body.body;
+
   _.each(classBody, function (node) {
     var methodName = node.key.name;
     var method     = node.value;
 
-    replaceInstanceSuperReferences(superName, method);
+    replaceInstanceSuperReferences(superName, method, methodName);
 
     if (methodName === "constructor") {
       if (node.kind === "") {
-        addConstructor(body[0], method);
+        hasConstructor = true;
+        addConstructor(construct, method);
       } else {
         throw util.errorWithNode(node, "unknown kind for constructor method");
       }
@@ -103,6 +107,12 @@ var buildClassBody = function (body, className, superName, node) {
     }
   });
 
+  if (!hasConstructor && superName) {
+    construct.body.body.push(util.template("class-super-constructor-call", {
+      SUPER_NAME: superName
+    }, true));
+  }
+
   if (!_.isEmpty(instanceMutatorMap)) {
     var protoId = util.template("prototype-identifier", {
       CLASS_NAME: className
@@ -116,51 +126,46 @@ var buildClassBody = function (body, className, superName, node) {
   }
 };
 
-var superIdentifier = function (superName, node, parent) {
+var superIdentifier = function (superName, methodName, node, parent) {
   if (parent.property === node) return;
 
   node.name = superName.name || superName.value;
 
-  // super(); -> ClassName.call(this);
+  // super(); -> ClassName.prototype.MethodName.call(this);
   if (parent.type === "CallExpression" && parent.callee === node) {
-    node.name += ".call";
+    if (methodName === "constructor") {
+      // constructor() { super(); }
+      node.name += ".call";
+    } else {
+      // foo() { super(); }
+      node.name += ".prototype." + methodName + ".call";
+    }
+
     parent.arguments.unshift(b.thisExpression());
+  } else if (parent.type === "MemberExpression") {
+    // super.test -> ClassName.prototype.test
+    node.name += ".prototype";
   }
 };
 
-var replaceInstanceSuperReferences = function (superName, method) {
+var replaceInstanceSuperReferences = function (superName, method, methodName) {
   superName = superName || b.literal("Function");
 
   traverse(method, function (node, parent) {
     if (node.type === "Identifier" && node.name === "super") {
-      superIdentifier(superName, node, parent);
-    } else if (node.type === "MemberExpression") {
-      // no accessing of super properties
-
-      if (isAccessingSuperProperties(parent, node)) {
-        throw util.errorWithNode(node, "cannot access super properties");
-      } else {
-        return;
-      }
+      superIdentifier(superName, methodName, node, parent);
     } else if (node.type === "CallExpression") {
       var callee = node.callee;
       if (callee.type !== "MemberExpression") return;
       if (callee.object.name !== "super") return;
 
-      callee.property.name = "prototype." + callee.property.name + ".call";
+      //  super.test(); -> Classname.prototype.MethodName.call(this);
+      callee.property.name = callee.property.name + ".call";
       node.arguments.unshift(b.thisExpression());
-    } else {
-      return;
     }
   });
 };
 
-var isAccessingSuperProperties = function (parent, node) {
-  var obj = node.object;
-  return obj.type === "Identifier" && obj.name === "super" &&
-         parent.object === node;
-};
-
 var addConstructor = function (construct, method) {
   construct.defaults = method.defaults;
   construct.params   = method.params;