Fix default descriptor setting for class properties with decorators (#7429)

(legacy decorators)

packages/babel-helpers/src/helpers.js

@@ -978,9 +978,7 @@ helpers.applyDecoratedDescriptor = helper("7.0.0-beta.0")`
         });
         desc.enumerable = !!desc.enumerable;
         desc.configurable = !!desc.configurable;
-        if ('value' in desc || desc.initializer){
+        desc.writable = !!desc.writable;
-            desc.writable = true;
-        }
 
         desc = decorators.slice().reverse().reduce(function(desc, decorator){
             return decorator(target, property, desc) || desc;

packages/babel-plugin-proposal-decorators/src/transformer-legacy.js

@@ -168,10 +168,18 @@ function applyTargetDecorators(path, state, decoratedProps) {
               decorators.map(dec => t.cloneNode(dec.expression)),
             ),
             t.objectExpression([
+              t.objectProperty(
+                t.identifier("configurable"),
+                t.booleanLiteral(true),
+              ),
               t.objectProperty(
                 t.identifier("enumerable"),
                 t.booleanLiteral(true),
               ),
+              t.objectProperty(
+                t.identifier("writable"),
+                t.booleanLiteral(true),
+              ),
               t.objectProperty(t.identifier("initializer"), initializer),
             ]),
           ]),

packages/babel-plugin-proposal-decorators/test/fixtures/legacy-class-prototype-properties/mutate-descriptor/exec.js

@@ -16,6 +16,16 @@ function dec(target, name, descriptor) {
   });
 }
 
+function plainDec(target, name, descriptor) {
+  expect(target).toBeTruthy();
+  expect(typeof name).toBe("string");
+  expect(typeof descriptor).toBe("object");
+
+  target.decoratedProps = (target.decoratedProps || []).concat([name]);
+
+  return descriptor;
+}
+
 class Example {
   @dec
   enumconfwrite = 1;
@@ -40,6 +50,9 @@ class Example {
 
   @dec
   _ = 8;
+
+  @plainDec
+  plain = 9;
 }
 
 const inst = new Example();
@@ -54,6 +67,7 @@ expect(inst.decoratedProps).toEqual([
   "conf",
   "write",
   "_",
+  "plain",
 ]);
 
 const descs = Object.getOwnPropertyDescriptors(inst);
@@ -97,3 +111,8 @@ expect(descs._.enumerable).toBe(false);
 expect(descs._.writable).toBe(false);
 expect(descs._.configurable).toBe(false);
 expect(inst._).toBe("__8__");
+
+expect(descs.plain.enumerable).toBeTruthy();
+expect(descs.plain.writable).toBeTruthy();
+expect(descs.plain.configurable).toBeTruthy();
+expect(inst.plain).toBe(9);

packages/babel-plugin-proposal-decorators/test/fixtures/legacy-class-prototype-properties/properties-without-initializer/exec.js

@@ -1,5 +1,11 @@
 function dec(target, name, descriptor) {
+  expect(target).toBeTruthy();
+  expect(typeof name).toBe("string");
+  expect(typeof descriptor).toBe("object");
 
+  target.decoratedProps = (target.decoratedProps || []).concat([name]);
+
+  return descriptor;
 }
 
 class Example {
@@ -7,5 +13,17 @@ class Example {
 }
 
 let inst = new Example();
+
+expect(Example.prototype).toHaveProperty("decoratedProps");
+expect(inst.decoratedProps).toEqual([
+  "prop",
+]);
+
 expect(inst).toHaveProperty("prop");
 expect(inst.prop).toBeUndefined();
+
+const descs = Object.getOwnPropertyDescriptors(inst);
+
+expect(descs.prop.enumerable).toBeTruthy();
+expect(descs.prop.writable).toBeTruthy();
+expect(descs.prop.configurable).toBeTruthy();

packages/babel-plugin-proposal-decorators/test/fixtures/legacy-decl-to-expression/method-decorators/output.mjs

@@ -1,6 +1,6 @@
 var _class, _class2;
 
-function _applyDecoratedDescriptor(target, property, decorators, descriptor, context) { var desc = {}; Object['ke' + 'ys'](descriptor).forEach(function (key) { desc[key] = descriptor[key]; }); desc.enumerable = !!desc.enumerable; desc.configurable = !!desc.configurable; if ('value' in desc || desc.initializer) { desc.writable = true; } desc = decorators.slice().reverse().reduce(function (desc, decorator) { return decorator(target, property, desc) || desc; }, desc); if (context && desc.initializer !== void 0) { desc.value = desc.initializer ? desc.initializer.call(context) : void 0; desc.initializer = undefined; } if (desc.initializer === void 0) { Object['define' + 'Property'](target, property, desc); desc = null; } return desc; }
+function _applyDecoratedDescriptor(target, property, decorators, descriptor, context) { var desc = {}; Object['ke' + 'ys'](descriptor).forEach(function (key) { desc[key] = descriptor[key]; }); desc.enumerable = !!desc.enumerable; desc.configurable = !!desc.configurable; desc.writable = !!desc.writable; desc = decorators.slice().reverse().reduce(function (desc, decorator) { return decorator(target, property, desc) || desc; }, desc); if (context && desc.initializer !== void 0) { desc.value = desc.initializer ? desc.initializer.call(context) : void 0; desc.initializer = undefined; } if (desc.initializer === void 0) { Object['define' + 'Property'](target, property, desc); desc = null; } return desc; }
 
 let A = (_class2 = class A {
   foo() {}

packages/babel-plugin-proposal-decorators/test/fixtures/legacy-regression/8041/output.mjs

@@ -1,6 +1,6 @@
 var _class2;
 
-function _applyDecoratedDescriptor(target, property, decorators, descriptor, context) { var desc = {}; Object['ke' + 'ys'](descriptor).forEach(function (key) { desc[key] = descriptor[key]; }); desc.enumerable = !!desc.enumerable; desc.configurable = !!desc.configurable; if ('value' in desc || desc.initializer) { desc.writable = true; } desc = decorators.slice().reverse().reduce(function (desc, decorator) { return decorator(target, property, desc) || desc; }, desc); if (context && desc.initializer !== void 0) { desc.value = desc.initializer ? desc.initializer.call(context) : void 0; desc.initializer = undefined; } if (desc.initializer === void 0) { Object['define' + 'Property'](target, property, desc); desc = null; } return desc; }
+function _applyDecoratedDescriptor(target, property, decorators, descriptor, context) { var desc = {}; Object['ke' + 'ys'](descriptor).forEach(function (key) { desc[key] = descriptor[key]; }); desc.enumerable = !!desc.enumerable; desc.configurable = !!desc.configurable; desc.writable = !!desc.writable; desc = decorators.slice().reverse().reduce(function (desc, decorator) { return decorator(target, property, desc) || desc; }, desc); if (context && desc.initializer !== void 0) { desc.value = desc.initializer ? desc.initializer.call(context) : void 0; desc.initializer = undefined; } if (desc.initializer === void 0) { Object['define' + 'Property'](target, property, desc); desc = null; } return desc; }
 
 let _class = (_class2 = class {
   bar() {}