Optimize the use of assertThisInitialized after super() (#16345)

* improve * add tests * remove thisSuper
babel · Mar 14, 2024 · da821bd · da821bd
1 parent dc891b6
commit da821bd
Show file tree

Hide file tree

Showing 54 changed files with 196 additions and 109 deletions.
diff --git a/packages/babel-helper-replace-supers/src/index.ts b/packages/babel-helper-replace-supers/src/index.ts
@@ -26,12 +26,11 @@ if (!process.env.BABEL_8_BREAKING && !USE_ESM && !IS_STANDALONE) {
   exports.skipAllButComputedKey = ns.skipAllButComputedKey;
 }
 
-type ThisRef =
-  | {
-      memo: t.AssignmentExpression;
-      this: t.Identifier;
-    }
-  | { this: t.ThisExpression };
+type ThisRef = {
+  needAccessFirst?: boolean;
+  this: t.ThisExpression;
+};
+
 /**
  * Creates an expression which result is the proto of objectRef.
  *
@@ -175,21 +174,18 @@ const specHandlers: SpecHandler = {
       this.isPrivateMethod,
     );
     return callExpression(this.file.addHelper("get"), [
-      // @ts-expect-error memo does not exist when this.isDerivedConstructor is false
-      thisRefs.memo ? sequenceExpression([thisRefs.memo, proto]) : proto,
+      thisRefs.needAccessFirst
+        ? sequenceExpression([thisRefs.this, proto])
+        : proto,
       this.prop(superMember),
       thisRefs.this,
     ]);
   },
 
   _getThisRefs(this: Handler & SpecHandler): ThisRef {
-    if (!this.isDerivedConstructor) {
-      return { this: thisExpression() };
-    }
-    const thisRef = this.scope.generateDeclaredUidIdentifier("thisSuper");
     return {
-      memo: assignmentExpression("=", thisRef, thisExpression()),
-      this: cloneNode(thisRef),
+      needAccessFirst: this.isDerivedConstructor,
+      this: thisExpression(),
     };
   },
 
@@ -206,8 +202,9 @@ const specHandlers: SpecHandler = {
       this.isPrivateMethod,
     );
     return callExpression(this.file.addHelper("set"), [
-      // @ts-expect-error memo does not exist when this.isDerivedConstructor is false
-      thisRefs.memo ? sequenceExpression([thisRefs.memo, proto]) : proto,
+      thisRefs.needAccessFirst
+        ? sequenceExpression([thisRefs.this, proto])
+        : proto,
       this.prop(superMember),
       value,
       thisRefs.this,

diff --git a/...form-class-properties/test/fixtures/nested-class/super-property-in-accessor-key/output.js b/...form-class-properties/test/fixtures/nested-class/super-property-in-accessor-key/output.js
@@ -14,11 +14,11 @@ let Hello = /*#__PURE__*/function () {
 let Outer = /*#__PURE__*/function (_Hello) {
   function Outer() {
     let _computedKey;
-    var _thisSuper, _this;
+    var _this;
     babelHelpers.classCallCheck(this, Outer);
     _this = babelHelpers.callSuper(this, Outer);
     var _A = /*#__PURE__*/new WeakMap();
-    _computedKey = babelHelpers.toPropertyKey(babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(Outer.prototype)), "toString", _thisSuper).call(_thisSuper));
+    _computedKey = babelHelpers.toPropertyKey(babelHelpers.get((_this, babelHelpers.getPrototypeOf(Outer.prototype)), "toString", _this).call(_this));
     let Inner = /*#__PURE__*/function (_computedKey4, _computedKey5) {
       function Inner() {
         babelHelpers.classCallCheck(this, Inner);

diff --git a/...ansform-class-properties/test/fixtures/nested-class/super-property-in-decorator/output.js b/...ansform-class-properties/test/fixtures/nested-class/super-property-in-decorator/output.js
@@ -15,7 +15,7 @@ let Outer = /*#__PURE__*/function (_Hello) {
   function Outer() {
     var _Inner;
     let _init_hello, _init_extra_hello;
-    var _thisSuper, _this;
+    var _this;
     babelHelpers.classCallCheck(this, Outer);
     _this = babelHelpers.callSuper(this, Outer);
     let Inner = /*#__PURE__*/babelHelpers.createClass(function Inner() {
@@ -24,7 +24,7 @@ let Outer = /*#__PURE__*/function (_Hello) {
       _init_extra_hello(this);
     });
     _Inner = Inner;
-    [_init_hello, _init_extra_hello] = babelHelpers.applyDecs2311(_Inner, [], [[babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(Outer.prototype)), "dec", _thisSuper), 0, "hello"]]).e;
+    [_init_hello, _init_extra_hello] = babelHelpers.applyDecs2311(_Inner, [], [[babelHelpers.get((_this, babelHelpers.getPrototypeOf(Outer.prototype)), "dec", _this), 0, "hello"]]).e;
     return babelHelpers.possibleConstructorReturn(_this, new Inner());
   }
   babelHelpers.inherits(Outer, _Hello);

diff --git a/...gin-transform-class-properties/test/fixtures/nested-class/super-property-in-key/output.js b/...gin-transform-class-properties/test/fixtures/nested-class/super-property-in-key/output.js
@@ -14,10 +14,10 @@ let Hello = /*#__PURE__*/function () {
 let Outer = /*#__PURE__*/function (_Hello) {
   function Outer() {
     let _babelHelpers$get$cal;
-    var _thisSuper, _this;
+    var _this;
     babelHelpers.classCallCheck(this, Outer);
     _this = babelHelpers.callSuper(this, Outer);
-    _babelHelpers$get$cal = babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(Outer.prototype)), "toString", _thisSuper).call(_thisSuper);
+    _babelHelpers$get$cal = babelHelpers.get((_this, babelHelpers.getPrototypeOf(Outer.prototype)), "toString", _this).call(_this);
     let Inner = /*#__PURE__*/babelHelpers.createClass(function Inner() {
       babelHelpers.classCallCheck(this, Inner);
       babelHelpers.defineProperty(this, _babelHelpers$get$cal, 'hello');

diff --git a/...ges/babel-plugin-transform-class-properties/test/fixtures/private-loose/derived/output.js b/...ges/babel-plugin-transform-class-properties/test/fixtures/private-loose/derived/output.js
@@ -16,7 +16,7 @@ var Bar = /*#__PURE__*/function (_Foo2) {
     var _this;
     babelHelpers.classCallCheck(this, Bar);
     _this = babelHelpers.callSuper(this, Bar, [...args]);
-    Object.defineProperty(babelHelpers.assertThisInitialized(_this), _prop2, {
+    Object.defineProperty(_this, _prop2, {
       writable: true,
       value: "bar"
     });

diff --git a/...ages/babel-plugin-transform-class-properties/test/fixtures/private-loose/foobar/output.js b/...ages/babel-plugin-transform-class-properties/test/fixtures/private-loose/foobar/output.js
@@ -6,7 +6,7 @@ let Child = /*#__PURE__*/function (_Parent) {
     var _this;
     babelHelpers.classCallCheck(this, Child);
     _this = babelHelpers.callSuper(this, Child);
-    Object.defineProperty(babelHelpers.assertThisInitialized(_this), _scopedFunctionWithThis, {
+    Object.defineProperty(_this, _scopedFunctionWithThis, {
       writable: true,
       value: function () {
         _this.name = {};

diff --git a/...properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js b/...properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js
@@ -20,7 +20,7 @@ var Foo = /*#__PURE__*/function () {
           var _this;
           babelHelpers.classCallCheck(this, Nested);
           _this = babelHelpers.callSuper(this, Nested, [...args]);
-          Object.defineProperty(babelHelpers.assertThisInitialized(_this), _foo2, {
+          Object.defineProperty(_this, _foo2, {
             writable: true,
             value: 3
           });

diff --git a/...form-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js b/...form-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js
@@ -19,7 +19,7 @@ var Foo = /*#__PURE__*/function () {
           var _this;
           babelHelpers.classCallCheck(this, Nested);
           _this = babelHelpers.callSuper(this, Nested, [...args]);
-          Object.defineProperty(babelHelpers.assertThisInitialized(_this), _foo2, {
+          Object.defineProperty(_this, _foo2, {
             writable: true,
             value: 3
           });

diff --git a/...l-plugin-transform-class-properties/test/fixtures/private-loose/super-statement/output.js b/...l-plugin-transform-class-properties/test/fixtures/private-loose/super-statement/output.js
@@ -6,7 +6,7 @@ var Foo = /*#__PURE__*/function (_Bar) {
     var _this;
     babelHelpers.classCallCheck(this, Foo);
     _this = babelHelpers.callSuper(this, Foo);
-    Object.defineProperty(babelHelpers.assertThisInitialized(_this), _bar, {
+    Object.defineProperty(_this, _bar, {
       writable: true,
       value: "foo"
     });

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/private/derived/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/private/derived/output.js
@@ -13,7 +13,7 @@ let Bar = /*#__PURE__*/function (_Foo2) {
     var _this;
     babelHelpers.classCallCheck(this, Bar);
     _this = babelHelpers.callSuper(this, Bar, [...args]);
-    babelHelpers.classPrivateFieldInitSpec(babelHelpers.assertThisInitialized(_this), _prop2, "bar");
+    babelHelpers.classPrivateFieldInitSpec(_this, _prop2, "bar");
     return _this;
   }
   babelHelpers.inherits(Bar, _Foo2);

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/private/foobar/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/private/foobar/output.js
@@ -6,7 +6,7 @@ let Child = /*#__PURE__*/function (_Parent) {
     var _this;
     babelHelpers.classCallCheck(this, Child);
     _this = babelHelpers.callSuper(this, Child);
-    babelHelpers.classPrivateFieldInitSpec(babelHelpers.assertThisInitialized(_this), _scopedFunctionWithThis, () => {
+    babelHelpers.classPrivateFieldInitSpec(_this, _scopedFunctionWithThis, () => {
       _this.name = {};
     });
     return _this;

diff --git a/...class-properties/test/fixtures/private/nested-class-extends-computed-redeclared/output.js b/...class-properties/test/fixtures/private/nested-class-extends-computed-redeclared/output.js
@@ -17,7 +17,7 @@ let Foo = /*#__PURE__*/function () {
           var _this;
           babelHelpers.classCallCheck(this, Nested);
           _this = babelHelpers.callSuper(this, Nested, [...args]);
-          babelHelpers.classPrivateFieldInitSpec(babelHelpers.assertThisInitialized(_this), _foo2, 3);
+          babelHelpers.classPrivateFieldInitSpec(_this, _foo2, 3);
           return _this;
         }
         babelHelpers.inherits(Nested, _ref);

diff --git a/...-transform-class-properties/test/fixtures/private/nested-class-extends-computed/output.js b/...-transform-class-properties/test/fixtures/private/nested-class-extends-computed/output.js
@@ -16,7 +16,7 @@ let Foo = /*#__PURE__*/function () {
           var _this;
           babelHelpers.classCallCheck(this, Nested);
           _this = babelHelpers.callSuper(this, Nested, [...args]);
-          babelHelpers.classPrivateFieldInitSpec(babelHelpers.assertThisInitialized(_this), _foo2, 3);
+          babelHelpers.classPrivateFieldInitSpec(_this, _foo2, 3);
           return _this;
         }
         babelHelpers.inherits(Nested, _ref);

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/private/super-call/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/private/super-call/output.js
@@ -16,10 +16,10 @@ let B = /*#__PURE__*/function (_A) {
   "use strict";
 
   function B(...args) {
-    var _thisSuper, _this;
+    var _this;
     babelHelpers.classCallCheck(this, B);
     _this = babelHelpers.callSuper(this, B, [...args]);
-    babelHelpers.classPrivateFieldInitSpec(babelHelpers.assertThisInitialized(_this), _foo, babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(B.prototype)), "foo", _thisSuper).call(_thisSuper));
+    babelHelpers.classPrivateFieldInitSpec(_this, _foo, babelHelpers.get((_this, babelHelpers.getPrototypeOf(B.prototype)), "foo", _this).call(_this));
     return _this;
   }
   babelHelpers.inherits(B, _A);

diff --git a/...s/babel-plugin-transform-class-properties/test/fixtures/private/super-statement/output.js b/...s/babel-plugin-transform-class-properties/test/fixtures/private/super-statement/output.js
@@ -6,7 +6,7 @@ let Foo = /*#__PURE__*/function (_Bar) {
     var _this;
     babelHelpers.classCallCheck(this, Foo);
     _this = babelHelpers.callSuper(this, Foo);
-    babelHelpers.classPrivateFieldInitSpec(babelHelpers.assertThisInitialized(_this), _bar, "foo");
+    babelHelpers.classPrivateFieldInitSpec(_this, _bar, "foo");
     return _this;
   }
   babelHelpers.inherits(Foo, _Bar);

diff --git a/...s/babel-plugin-transform-class-properties/test/fixtures/public-loose/super-call/output.js b/...s/babel-plugin-transform-class-properties/test/fixtures/public-loose/super-call/output.js
@@ -15,10 +15,10 @@ var B = /*#__PURE__*/function (_A) {
   "use strict";
 
   function B(...args) {
-    var _thisSuper, _this;
+    var _this;
     babelHelpers.classCallCheck(this, B);
     _this = babelHelpers.callSuper(this, B, [...args]);
-    _this.foo = babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(B.prototype)), "foo", _thisSuper).call(_thisSuper);
+    _this.foo = babelHelpers.get((_this, babelHelpers.getPrototypeOf(B.prototype)), "foo", _this).call(_this);
     return _this;
   }
   babelHelpers.inherits(B, _A);

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/public/derived/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/public/derived/output.js
@@ -5,7 +5,7 @@ var Foo = /*#__PURE__*/function (_Bar) {
     var _this;
     babelHelpers.classCallCheck(this, Foo);
     _this = babelHelpers.callSuper(this, Foo, [...args]);
-    babelHelpers.defineProperty(babelHelpers.assertThisInitialized(_this), "bar", "foo");
+    babelHelpers.defineProperty(_this, "bar", "foo");
     return _this;
   }
   babelHelpers.inherits(Foo, _Bar);

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/public/foobar/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/public/foobar/output.js
@@ -5,7 +5,7 @@ var Child = /*#__PURE__*/function (_Parent) {
     var _this;
     babelHelpers.classCallCheck(this, Child);
     _this = babelHelpers.callSuper(this, Child);
-    babelHelpers.defineProperty(babelHelpers.assertThisInitialized(_this), "scopedFunctionWithThis", function () {
+    babelHelpers.defineProperty(_this, "scopedFunctionWithThis", function () {
       _this.name = {};
     });
     return _this;

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/public/super-call/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/public/super-call/output.js
@@ -15,10 +15,10 @@ var B = /*#__PURE__*/function (_A) {
   "use strict";
 
   function B(...args) {
-    var _thisSuper, _this;
+    var _this;
     babelHelpers.classCallCheck(this, B);
     _this = babelHelpers.callSuper(this, B, [...args]);
-    babelHelpers.defineProperty(babelHelpers.assertThisInitialized(_this), "foo", babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(B.prototype)), "foo", _thisSuper).call(_thisSuper));
+    babelHelpers.defineProperty(_this, "foo", babelHelpers.get((_this, babelHelpers.getPrototypeOf(B.prototype)), "foo", _this).call(_this));
     return _this;
   }
   babelHelpers.inherits(B, _A);

diff --git a/...es/babel-plugin-transform-class-properties/test/fixtures/public/super-statement/output.js b/...es/babel-plugin-transform-class-properties/test/fixtures/public/super-statement/output.js
@@ -5,7 +5,7 @@ var Foo = /*#__PURE__*/function (_Bar) {
     var _this;
     babelHelpers.classCallCheck(this, Foo);
     _this = babelHelpers.callSuper(this, Foo);
-    babelHelpers.defineProperty(babelHelpers.assertThisInitialized(_this), "bar", "foo");
+    babelHelpers.defineProperty(_this, "bar", "foo");
     return _this;
   }
   babelHelpers.inherits(Foo, _Bar);

diff --git a/packages/babel-plugin-transform-class-properties/test/fixtures/regression/6154/output.js b/packages/babel-plugin-transform-class-properties/test/fixtures/regression/6154/output.js
@@ -5,14 +5,14 @@ var Test = /*#__PURE__*/babelHelpers.createClass(function Test() {
   babelHelpers.classCallCheck(this, Test);
   var Other = /*#__PURE__*/function (_Test) {
     function Other() {
-      var _thisSuper, _this;
+      var _this;
       babelHelpers.classCallCheck(this, Other);
       for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
         args[_key] = arguments[_key];
       }
       _this = babelHelpers.callSuper(this, Other, [].concat(args));
-      babelHelpers.defineProperty(babelHelpers.assertThisInitialized(_this), "a", function () {
-        return babelHelpers.get((_thisSuper = babelHelpers.assertThisInitialized(_this), babelHelpers.getPrototypeOf(Other.prototype)), "test", _thisSuper);
+      babelHelpers.defineProperty(_this, "a", function () {
+        return babelHelpers.get((_this, babelHelpers.getPrototypeOf(Other.prototype)), "test", _this);
       });
       return _this;
     }

diff --git a/packages/babel-plugin-transform-classes/src/transformClass.ts b/packages/babel-plugin-transform-classes/src/transformClass.ts
@@ -398,10 +398,15 @@ export default function transformClass(
     const path = classState.userConstructorPath;
     const body = path.get("body");
 
+    const constructorBody = path.get("body");
+
+    let maxGuaranteedSuperBeforeIndex = constructorBody.node.body.length;
+
     path.traverse(findThisesVisitor);
 
     let thisRef = function () {
       const ref = path.scope.generateDeclaredUidIdentifier("this");
+      maxGuaranteedSuperBeforeIndex++;
       thisRef = () => t.cloneNode(ref);
       return ref;
     };
@@ -413,15 +418,6 @@ export default function transformClass(
       );
     };
 
-    for (const thisPath of classState.superThises) {
-      const { node, parentPath } = thisPath;
-      if (parentPath.isMemberExpression({ object: node })) {
-        thisPath.replaceWith(thisRef());
-        continue;
-      }
-      thisPath.replaceWith(buildAssertThisInitialized());
-    }
-
     const bareSupers: NodePath<t.CallExpression>[] = [];
     path.traverse(
       traverse.visitors.merge([
@@ -437,15 +433,18 @@ export default function transformClass(
       ]),
     );
 
-    let guaranteedSuperBeforeFinish = !!bareSupers.length;
-
     for (const bareSuper of bareSupers) {
       wrapSuperCall(bareSuper, classState.superName, thisRef, body);
 
-      if (guaranteedSuperBeforeFinish) {
+      if (maxGuaranteedSuperBeforeIndex >= 0) {
+        let lastParentPath: NodePath;
         bareSuper.find(function (parentPath) {
           // hit top so short circuit
-          if (parentPath === path) {
+          if (parentPath === constructorBody) {
+            maxGuaranteedSuperBeforeIndex = Math.min(
+              maxGuaranteedSuperBeforeIndex,
+              lastParentPath.key as number,
+            );
             return true;
           }
 
@@ -454,13 +453,40 @@ export default function transformClass(
             parentPath.isConditional() ||
             parentPath.isArrowFunctionExpression()
           ) {
-            guaranteedSuperBeforeFinish = false;
+            maxGuaranteedSuperBeforeIndex = -1;
             return true;
           }
+
+          lastParentPath = parentPath;
         });
       }
     }
 
+    for (const thisPath of classState.superThises) {
+      const { node, parentPath } = thisPath;
+      if (parentPath.isMemberExpression({ object: node })) {
+        thisPath.replaceWith(thisRef());
+        continue;
+      }
+
+      let thisIndex: number;
+      thisPath.find(function (parentPath) {
+        if (parentPath.parentPath === constructorBody) {
+          thisIndex = parentPath.key as number;
+          return true;
+        }
+      });
+
+      if (
+        maxGuaranteedSuperBeforeIndex != -1 &&
+        thisIndex > maxGuaranteedSuperBeforeIndex
+      ) {
+        thisPath.replaceWith(thisRef());
+      } else {
+        thisPath.replaceWith(buildAssertThisInitialized());
+      }
+    }
+
     let wrapReturn;
 
     if (classState.isLoose) {
@@ -486,6 +512,9 @@ export default function transformClass(
     // if we have a return as the last node in the body then we've already caught that
     // return
     const bodyPaths = body.get("body");
+    const guaranteedSuperBeforeFinish =
+      maxGuaranteedSuperBeforeIndex !== -1 &&
+      maxGuaranteedSuperBeforeIndex < bodyPaths.length;
     if (!bodyPaths.length || !bodyPaths.pop().isReturnStatement()) {
       body.pushContainer(
         "body",

diff --git a/...-transform-classes/test/fixtures/assumption-constantSuper/accessing-super-class/output.js b/...-transform-classes/test/fixtures/assumption-constantSuper/accessing-super-class/output.js
@@ -7,11 +7,11 @@ var Test = /*#__PURE__*/function (_Foo) {
     babelHelpers.classCallCheck(this, Test);
     woops.super.test();
     _this = babelHelpers.callSuper(this, Test);
-    _Foo.prototype.test.call(babelHelpers.assertThisInitialized(_this));
+    _Foo.prototype.test.call(_this);
     _this = babelHelpers.callSuper(this, Test, arguments);
     _this = babelHelpers.callSuper(this, Test, ["test"].concat(Array.prototype.slice.call(arguments)));
-    _Foo.prototype.test.apply(babelHelpers.assertThisInitialized(_this), arguments);
-    (_Foo$prototype$test = _Foo.prototype.test).call.apply(_Foo$prototype$test, [babelHelpers.assertThisInitialized(_this), "test"].concat(Array.prototype.slice.call(arguments)));
+    _Foo.prototype.test.apply(_this, arguments);
+    (_Foo$prototype$test = _Foo.prototype.test).call.apply(_Foo$prototype$test, [_this, "test"].concat(Array.prototype.slice.call(arguments)));
     return _this;
   }
   babelHelpers.inherits(Test, _Foo);