Mark WeakMaps of private fields as pure

packages/babel-helper-create-class-features-plugin/package.json

@@ -18,6 +18,7 @@
     "babel-plugin"
   ],
   "dependencies": {
+    "@babel/helper-annotate-as-pure": "workspace:^7.12.13",
     "@babel/helper-function-name": "workspace:^7.12.13",
     "@babel/helper-member-expression-to-functions": "workspace:^7.13.0",
     "@babel/helper-optimise-call-expression": "workspace:^7.12.13",

packages/babel-helper-create-class-features-plugin/src/fields.js

@@ -4,6 +4,7 @@ import ReplaceSupers, {
 } from "@babel/helper-replace-supers";
 import memberExpressionToFunctions from "@babel/helper-member-expression-to-functions";
 import optimiseCall from "@babel/helper-optimise-call-expression";
+import annotateAsPure from "@babel/helper-annotate-as-pure";
 
 import * as ts from "./typescript";
 
@@ -53,20 +54,23 @@ export function buildPrivateNamesNodes(
     const { static: isStatic, method: isMethod, getId, setId } = value;
     const isAccessor = getId || setId;
     const id = t.cloneNode(value.id);
+
+    let init;
+
     if (privateFieldsAsProperties) {
-      initNodes.push(
-        template.statement.ast`
-          var ${id} = ${state.addHelper("classPrivateFieldLooseKey")}("${name}")
-        `,
-      );
-    } else if (isMethod && !isStatic) {
-      if (isAccessor) {
-        initNodes.push(template.statement.ast`var ${id} = new WeakMap();`);
-      } else {
-        initNodes.push(template.statement.ast`var ${id} = new WeakSet();`);
-      }
+      init = t.callExpression(state.addHelper("classPrivateFieldLooseKey"), [
+        t.stringLiteral(name),
+      ]);
     } else if (!isStatic) {
-      initNodes.push(template.statement.ast`var ${id} = new WeakMap();`);
+      init = t.newExpression(
+        t.identifier(!isMethod || isAccessor ? "WeakMap" : "WeakSet"),
+        [],
+      );
+    }
+
+    if (init) {
+      annotateAsPure(init);
+      initNodes.push(template.statement.ast`var ${id} = ${init}`);
     }
   }
 

packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-false/output.js

@@ -1,4 +1,4 @@
-var _privateMethod = new WeakSet();
+var _privateMethod = /*#__PURE__*/new WeakSet();
 
 class X {
   constructor() {

packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-private-methods/loose-true/output.js

@@ -1,4 +1,4 @@
-var _privateMethod = babelHelpers.classPrivateFieldLooseKey("privateMethod");
+var _privateMethod = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("privateMethod");
 
 class X {
   constructor() {

packages/babel-helper-create-class-features-plugin/test/fixtures/replace-supers/method/output.js

@@ -1,4 +1,4 @@
-var _foo = new WeakSet();
+var _foo = /*#__PURE__*/new WeakSet();
 
 class A extends B {
   constructor(...args) {

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration-optional-chaining/output.mjs

@@ -1,4 +1,4 @@
-var _m = new WeakMap();
+var _m = /*#__PURE__*/new WeakMap();
 
 class C {
   constructor() {

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private-integration/output.mjs

@@ -1,4 +1,4 @@
-var _m = new WeakMap();
+var _m = /*#__PURE__*/new WeakMap();
 
 class C {
   constructor() {

packages/babel-plugin-proposal-async-generator-functions/test/fixtures/async-generators/class-private-method/output.js

@@ -1,4 +1,4 @@
-var _g = new WeakSet();
+var _g = /*#__PURE__*/new WeakSet();
 
 class C {
   constructor() {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/assignment/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/call/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/canonical/output.js

@@ -1,6 +1,6 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
-var _y = babelHelpers.classPrivateFieldLooseKey("y");
+var _y = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("y");
 
 var Point = /*#__PURE__*/function () {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/constructor-collision/output.js

@@ -1,6 +1,6 @@
 var foo = "bar";
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = function Foo() {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/declaration-order/output.js

@@ -1,4 +1,4 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
 var C = function C() {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived-multiple-supers/output.js

@@ -1,4 +1,4 @@
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = /*#__PURE__*/function (_Bar) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/derived/output.js

@@ -1,4 +1,4 @@
-var _prop = babelHelpers.classPrivateFieldLooseKey("prop");
+var _prop = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("prop");
 
 var Foo = function Foo() {
   "use strict";
@@ -10,7 +10,7 @@ var Foo = function Foo() {
   });
 };
 
-var _prop2 = babelHelpers.classPrivateFieldLooseKey("prop");
+var _prop2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("prop");
 
 var Bar = /*#__PURE__*/function (_Foo) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-static/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-3/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-static/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern/output.js

@@ -1,4 +1,4 @@
-var _client = babelHelpers.classPrivateFieldLooseKey("client");
+var _client = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("client");
 
 var Foo = function Foo(props) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/extracted-this/output.js

@@ -1,8 +1,8 @@
 var foo = "bar";
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
-var _baz = babelHelpers.classPrivateFieldLooseKey("baz");
+var _baz = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("baz");
 
 var Foo = function Foo(_foo) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/foobar/output.js

@@ -1,4 +1,4 @@
-var _scopedFunctionWithThis = babelHelpers.classPrivateFieldLooseKey("scopedFunctionWithThis");
+var _scopedFunctionWithThis = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("scopedFunctionWithThis");
 
 var Child = /*#__PURE__*/function (_Parent) {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance-undefined/output.js

@@ -1,4 +1,4 @@
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = function Foo() {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/instance/output.js

@@ -1,4 +1,4 @@
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = function Foo() {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/logical-assignment/output.js

@@ -1,8 +1,8 @@
-var _nullish = babelHelpers.classPrivateFieldLooseKey("nullish");
+var _nullish = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("nullish");
 
-var _and = babelHelpers.classPrivateFieldLooseKey("and");
+var _and = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("and");
 
-var _or = babelHelpers.classPrivateFieldLooseKey("or");
+var _or = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("or");
 
 class Foo {
   constructor() {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/multiple/output.js

@@ -1,6 +1,6 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
-var _y = babelHelpers.classPrivateFieldLooseKey("y");
+var _y = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("y");
 
 var Foo = function Foo() {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/native-classes/output.js

@@ -1,6 +1,6 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 class Foo {
   constructor() {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed-redeclared/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
@@ -16,7 +16,7 @@ var Foo = /*#__PURE__*/function () {
     value: function test() {
       var _babelHelpers$classPr;
 
-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       _babelHelpers$classPr = babelHelpers.classPrivateFieldLooseBase(this, _foo2)[_foo2];
 

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-computed/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed-redeclared/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
@@ -18,7 +18,7 @@ var Foo = /*#__PURE__*/function () {
 
       var _babelHelpers$classPr;
 
-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       var Nested = /*#__PURE__*/function (_ref) {
         babelHelpers.inherits(Nested, _ref);
@@ -38,7 +38,7 @@ var Foo = /*#__PURE__*/function () {
         }
 
         return Nested;
-      }((_foo3 = babelHelpers.classPrivateFieldLooseKey("foo"), _babelHelpers$classPr = babelHelpers.classPrivateFieldLooseBase(this, _foo3)[_foo3], /*#__PURE__*/function () {
+      }((_foo3 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo"), _babelHelpers$classPr = babelHelpers.classPrivateFieldLooseBase(this, _foo3)[_foo3], /*#__PURE__*/function () {
         function _class2() {
           babelHelpers.classCallCheck(this, _class2);
           Object.defineProperty(this, _foo3, {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-extends-computed/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
@@ -16,7 +16,7 @@ var Foo = /*#__PURE__*/function () {
     value: function test() {
       var _babelHelpers$classPr;
 
-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       var Nested = /*#__PURE__*/function (_ref) {
         babelHelpers.inherits(Nested, _ref);

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-other-redeclared/output.js

@@ -1,6 +1,6 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
-var _bar = babelHelpers.classPrivateFieldLooseKey("bar");
+var _bar = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
@@ -20,7 +20,7 @@ var Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _bar2 = babelHelpers.classPrivateFieldLooseKey("bar");
+      var _bar2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("bar");
 
       var Nested = /*#__PURE__*/function () {
         function Nested() {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class-redeclared/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";
@@ -14,7 +14,7 @@ var Foo = /*#__PURE__*/function () {
   babelHelpers.createClass(Foo, [{
     key: "test",
     value: function test() {
-      var _foo2 = babelHelpers.classPrivateFieldLooseKey("foo");
+      var _foo2 = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
       var Nested = /*#__PURE__*/function () {
         function Nested() {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/nested-class/output.js

@@ -1,4 +1,4 @@
-var _foo = babelHelpers.classPrivateFieldLooseKey("foo");
+var _foo = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("foo");
 
 var Foo = /*#__PURE__*/function () {
   "use strict";

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/non-block-arrow-func/output.mjs

@@ -1,7 +1,7 @@
 export default (param => {
   var _class, _props, _temp;
 
-  return _temp = (_props = babelHelpers.classPrivateFieldLooseKey("props"), _class = class App {
+  return _temp = (_props = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("props"), _class = class App {
     getParam() {
       return param;
     }

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call-with-transform/output.js

@@ -1,8 +1,8 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
-var _m = babelHelpers.classPrivateFieldLooseKey("m");
+var _m = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("m");
 
-var _self = babelHelpers.classPrivateFieldLooseKey("self");
+var _self = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("self");
 
 class Foo {
   static getSelf() {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/optional-chain-before-member-call/output.js

@@ -1,8 +1,8 @@
-var _x = babelHelpers.classPrivateFieldLooseKey("x");
+var _x = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("x");
 
-var _m = babelHelpers.classPrivateFieldLooseKey("m");
+var _m = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("m");
 
-var _self = babelHelpers.classPrivateFieldLooseKey("self");
+var _self = /*#__PURE__*/babelHelpers.classPrivateFieldLooseKey("self");
 
 class Foo {
   static getSelf() {