Merge pull request #408 from 6to5/fix-esnext-class-tests

[WIP] Fix super with getters and setters and with class prototypes changing.

lib/6to5/file.js

@@ -36,7 +36,8 @@ File.helpers = [
   "interop-require-wildcard",
   "typeof",
   "exports-wildcard",
-  "extends"
+  "extends",
+  "get"
 ];
 
 File.excludeHelpersFromRuntime = [

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

@@ -1,3 +1,3 @@
-if (SUPER_NAME !== null) {
-  SUPER_NAME.apply(this, arguments);
+if (Object.getPrototypeOf(CLASS_NAME) !== null) {
+  Object.getPrototypeOf(CLASS_NAME).apply(this, arguments);
 }

lib/6to5/transformation/templates/get.js

@@ -0,0 +1,23 @@
+(function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+
+    if (getter === undefined) {
+      return undefined;
+    }
+
+    return getter.call(receiver);
+  }
+});

lib/6to5/transformation/transformers/es6-classes.js

@@ -149,7 +149,7 @@ Class.prototype.buildBody = function () {
 
   if (!this.hasConstructor && superName && !t.isFalsyExpression(superName)) {
     constructor.body.body.push(util.template("class-super-constructor-call", {
-      SUPER_NAME: superName
+      CLASS_NAME: className
     }, true));
   }
 
@@ -215,45 +215,45 @@ Class.prototype.pushMethod = function (node) {
 };
 
 /**
- * Given a `methodNode`, produce a `MemberExpression` super class reference.
+ * Gets a node representing the super class value of the named property.
  *
- * @param {Node} methodNode MethodDefinition
- * @param {Node} node Identifier
- * @param {Node} parent
+ * @example
+ *
+ *   _get(Object.getPrototypeOf(CLASS.prototype), "METHOD", this)
+ *
+ * @param {Node} property
+ * @param {boolean} isStatic
+ * @param {boolean} isComputed
  *
  * @returns {Node}
  */
 
-Class.prototype.superIdentifier = function (methodNode, id, parent) {
-  var methodName = methodNode.key;
-  var superName  = this.superName || t.identifier("Function");
-
-  if (parent.property === id) {
-    return;
-  } else if (t.isCallExpression(parent, { callee: id })) {
-    // super(); -> ClassName.prototype.MethodName.call(this);
-    parent.arguments.unshift(t.thisExpression());
-
-    if (methodName.name === "constructor") {
-      // constructor() { super(); }
-      return t.memberExpression(superName, t.identifier("call"));
-    } else {
-      id = superName;
-
-      // foo() { super(); }
-      if (!methodNode.static) {
-        id = t.memberExpression(id, t.identifier("prototype"));
-      }
-
-      id = t.memberExpression(id, methodName, methodNode.computed);
-      return t.memberExpression(id, t.identifier("call"));
-    }
-  } else if (t.isMemberExpression(parent) && !methodNode.static) {
-    // super.test -> ClassName.prototype.test
-    return t.memberExpression(superName, t.identifier("prototype"));
-  } else {
-    return superName;
-  }
+Class.prototype.superProperty = function (property, isStatic, isComputed) {
+  return t.callExpression(
+    this.file.addHelper("get"),
+    [
+      t.callExpression(
+        t.memberExpression(
+          t.identifier("Object"),
+          t.identifier("getPrototypeOf"),
+          false
+        ),
+        [
+          isStatic ?
+            this.className :
+            t.memberExpression(
+              this.className,
+              t.identifier("prototype"),
+              false
+            )
+        ]
+      ),
+      isComputed ?
+        property :
+        t.literal(property.name),
+      t.thisExpression()
+    ]
+  );
 };
 
 /**
@@ -268,16 +268,48 @@ Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
 
   traverse(method, {
     enter: function (node, parent) {
+      var property;
+      var computed;
+      var args;
+
       if (t.isIdentifier(node, { name: "super" })) {
-        return self.superIdentifier(methodNode, node, parent);
+        if (!(t.isMemberExpression(parent) && !parent.computed && parent.property === node)) {
+          throw self.file.errorWithNode(node, "illegal use of bare super");
+        }
       } else if (t.isCallExpression(node)) {
         var callee = node.callee;
-        if (!t.isMemberExpression(callee)) return;
-        if (callee.object.name !== "super") return;
+        if (t.isIdentifier(callee) && callee.name === "super") {
+          // super(); -> _get(Object.getPrototypeOf(ClassName), "MethodName", this).call(this);
+          property = methodNode.key;
+          computed = methodNode.computed;
+          args = node.arguments;
+        } else {
+          if (!t.isMemberExpression(callee)) return;
+          if (callee.object.name !== "super") return;
 
-        // super.test(); -> ClassName.prototype.MethodName.call(this);
-        t.appendToMemberExpression(callee, t.identifier("call"));
-        node.arguments.unshift(t.thisExpression());
+          // super.test(); -> _get(Object.getPrototypeOf(ClassName.prototype), "test", this).call(this);
+          property = callee.property;
+          computed = callee.computed;
+          args = node.arguments;
+        }
+      } else if (t.isMemberExpression(node)) {
+        if (!t.isIdentifier(node.object, { name: "super" })) return;
+
+        // super.name; -> _get(Object.getPrototypeOf(ClassName.prototype), "name", this);
+        property = node.property;
+        computed = node.computed;
+      }
+
+      if (property) {
+        var superProperty = self.superProperty(property, methodNode.static, computed);
+        if (args) {
+          return t.callExpression(
+            t.memberExpression(superProperty, t.identifier("call"), false),
+            [t.thisExpression()].concat(args)
+          );
+        } else {
+          return superProperty;
+        }
       }
     }
   });