Implement @babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining (#13009)

Gulpfile.mjs

@@ -426,6 +426,7 @@ const libBundles = [
   "packages/babel-plugin-proposal-optional-chaining",
   "packages/babel-preset-typescript",
   "packages/babel-helper-member-expression-to-functions",
+  "packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining",
 ].map(src => ({
   src,
   format: "cjs",

lib/babel-packages.js.flow

@@ -166,7 +166,9 @@ declare module "@babel/helper-function-name" {
 }
 
 declare module "@babel/helper-split-export-declaration" {
-  declare export default function splitExportDeclaration(exportDeclaration: any): any;
+  declare export default function splitExportDeclaration(
+    exportDeclaration: any
+  ): any;
 }
 
 declare module "@babel/traverse" {
@@ -196,6 +198,13 @@ declare module "@babel/highlight" {
   /**
    * Highlight `code`.
    */
-  declare export default function highlight(code: string, options?: Options): string;
+  declare export default function highlight(
-    declare export { getChalk, shouldHighlight };
+    code: string,
+    options?: Options
+  ): string;
+  declare export { getChalk, shouldHighlight };
+}
+
+declare module "@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining" {
+  declare module.exports: any;
 }

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/.npmignore

@@ -0,0 +1,3 @@
+src
+test
+*.log

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/README.md

@@ -0,0 +1,19 @@
+# @babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining
+
+> Transform optional chaining operators to workaround a [v8 bug](https://crbug.com/v8/11558).
+
+See our website [@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining](https://babeljs.io/docs/en/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining --dev
+```

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining",
+  "version": "7.13.8",
+  "description": "Transform optional chaining operators to workaround https://crbug.com/v8/11558",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/babel/babel.git",
+    "directory": "packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining"
+  },
+  "homepage": "https://babel.dev/docs/en/next/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining",
+  "license": "MIT",
+  "publishConfig": {
+    "access": "public"
+  },
+  "main": "lib/index.js",
+  "exports": {
+    ".": [
+      "./lib/index.js"
+    ]
+  },
+  "keywords": [
+    "babel-plugin",
+    "bugfix"
+  ],
+  "dependencies": {
+    "@babel/helper-plugin-utils": "workspace:^7.13.0",
+    "@babel/helper-skip-transparent-expression-wrappers": "workspace:^7.12.1",
+    "@babel/plugin-proposal-optional-chaining": "workspace:^7.13.8"
+  },
+  "peerDependencies": {
+    "@babel/core": "^7.13.0"
+  },
+  "devDependencies": {
+    "@babel/core": "workspace:*",
+    "@babel/helper-plugin-test-runner": "workspace:*",
+    "@babel/traverse": "workspace:*"
+  }
+}

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/index.ts

@@ -0,0 +1,22 @@
+import { declare } from "@babel/helper-plugin-utils";
+import { transform } from "@babel/plugin-proposal-optional-chaining";
+import { shouldTransform } from "./util";
+
+export default declare(api => {
+  api.assertVersion(7);
+
+  const noDocumentAll = api.assumption("noDocumentAll");
+  const pureGetters = api.assumption("pureGetters");
+
+  return {
+    name: "bugfix-v8-spread-parameters-in-optional-chaining",
+
+    visitor: {
+      "OptionalCallExpression|OptionalMemberExpression"(path) {
+        if (shouldTransform(path)) {
+          transform(path, { noDocumentAll, pureGetters });
+        }
+      },
+    },
+  };
+});

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts

@@ -0,0 +1,59 @@
+import { skipTransparentExprWrappers } from "@babel/helper-skip-transparent-expression-wrappers";
+import type { NodePath } from "@babel/traverse";
+import { types as t } from "@babel/core";
+// https://crbug.com/v8/11558
+
+// check if there is a spread element followed by another argument.
+// (...[], 0) or (...[], ...[])
+
+function matchAffectedArguments(argumentNodes) {
+  const spreadIndex = argumentNodes.findIndex(node => t.isSpreadElement(node));
+  return spreadIndex >= 0 && spreadIndex !== argumentNodes.length - 1;
+}
+
+/**
+ * Check whether the optional chain is affected by https://crbug.com/v8/11558.
+ * This routine MUST not manipulate NodePath
+ *
+ * @export
+ * @param {(NodePath<t.OptionalMemberExpression | t.OptionalCallExpression>)} path
+ * @returns {boolean}
+ */
+export function shouldTransform(
+  path: NodePath<t.OptionalMemberExpression | t.OptionalCallExpression>,
+): boolean {
+  let optionalPath = path;
+  const chains = [];
+  while (
+    optionalPath.isOptionalMemberExpression() ||
+    optionalPath.isOptionalCallExpression()
+  ) {
+    const { node } = optionalPath;
+    chains.push(node);
+
+    if (optionalPath.isOptionalMemberExpression()) {
+      optionalPath = skipTransparentExprWrappers(optionalPath.get("object"));
+    } else if (optionalPath.isOptionalCallExpression()) {
+      optionalPath = skipTransparentExprWrappers(optionalPath.get("callee"));
+    }
+  }
+  for (let i = 0; i < chains.length; i++) {
+    const node = chains[i];
+    if (
+      t.isOptionalCallExpression(node) &&
+      matchAffectedArguments(node.arguments)
+    ) {
+      // f?.(...[], 0)
+      if (node.optional) {
+        return true;
+      }
+      // o?.m(...[], 0)
+      // when node.optional is false, chains[i + 1] is always well defined
+      const callee = chains[i + 1];
+      if (t.isOptionalMemberExpression(callee, { optional: true })) {
+        return true;
+      }
+    }
+  }
+  return false;
+}

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/assumption-noDocumentAll/basic/input.mjs

@@ -0,0 +1,7 @@
+fn?.(...b, 1);
+
+a?.b(...c, 1);
+
+a?.b?.(...c, 1);
+
+a.b?.(...c, 1);

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/assumption-noDocumentAll/basic/output.mjs

@@ -0,0 +1,6 @@
+var _fn, _a, _a2, _a2$b, _a$b, _a3;
+
+(_fn = fn) === null || _fn === void 0 ? void 0 : _fn(...b, 1);
+(_a = a) === null || _a === void 0 ? void 0 : _a.b(...c, 1);
+(_a2 = a) === null || _a2 === void 0 ? void 0 : (_a2$b = _a2.b) === null || _a2$b === void 0 ? void 0 : _a2$b.call(_a2, ...c, 1);
+(_a$b = (_a3 = a).b) === null || _a$b === void 0 ? void 0 : _a$b.call(_a3, ...c, 1);

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/assumption-pureGetters/function-call/input.js

@@ -0,0 +1,19 @@
+foo?.(...[], 1);
+
+foo?.bar(...[], 1)
+
+foo.bar?.(foo.bar, ...[], 1)
+
+foo?.bar?.(foo.bar, ...[], 1)
+
+foo?.(...[], 1).bar
+
+foo?.(...[], 1)?.bar
+
+foo.bar?.(...[], 1).baz
+
+foo.bar?.(...[], 1)?.baz
+
+foo?.bar?.(...[], 1).baz
+
+foo?.bar?.(...[], 1)?.baz

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/assumption-pureGetters/function-call/output.js

@@ -0,0 +1,12 @@
+var _foo, _foo2, _foo$bar, _foo3, _foo4, _foo4$bar, _foo5, _foo6, _foo7, _foo$bar2, _foo8, _foo$bar3, _foo9, _foo$bar3$call, _foo10, _foo10$bar, _foo11, _foo11$bar, _foo11$bar$call;
+
+(_foo = foo) === null || _foo === void 0 ? void 0 : _foo(...[], 1);
+(_foo2 = foo) === null || _foo2 === void 0 ? void 0 : _foo2.bar(...[], 1);
+(_foo$bar = (_foo3 = foo).bar) === null || _foo$bar === void 0 ? void 0 : _foo$bar.call(_foo3, foo.bar, ...[], 1);
+(_foo4 = foo) === null || _foo4 === void 0 ? void 0 : (_foo4$bar = _foo4.bar) === null || _foo4$bar === void 0 ? void 0 : _foo4$bar.call(_foo4, foo.bar, ...[], 1);
+(_foo5 = foo) === null || _foo5 === void 0 ? void 0 : _foo5(...[], 1).bar;
+(_foo6 = foo) === null || _foo6 === void 0 ? void 0 : (_foo7 = _foo6(...[], 1)) === null || _foo7 === void 0 ? void 0 : _foo7.bar;
+(_foo$bar2 = (_foo8 = foo).bar) === null || _foo$bar2 === void 0 ? void 0 : _foo$bar2.call(_foo8, ...[], 1).baz;
+(_foo$bar3 = (_foo9 = foo).bar) === null || _foo$bar3 === void 0 ? void 0 : (_foo$bar3$call = _foo$bar3.call(_foo9, ...[], 1)) === null || _foo$bar3$call === void 0 ? void 0 : _foo$bar3$call.baz;
+(_foo10 = foo) === null || _foo10 === void 0 ? void 0 : (_foo10$bar = _foo10.bar) === null || _foo10$bar === void 0 ? void 0 : _foo10$bar.call(_foo10, ...[], 1).baz;
+(_foo11 = foo) === null || _foo11 === void 0 ? void 0 : (_foo11$bar = _foo11.bar) === null || _foo11$bar === void 0 ? void 0 : (_foo11$bar$call = _foo11$bar.call(_foo11, ...[], 1)) === null || _foo11$bar$call === void 0 ? void 0 : _foo11$bar$call.baz;

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

@@ -0,0 +1,5 @@
+fn?.(...b, 1);
+
+a?.b(...c, 1);
+
+a?.b?.(...c, 1);

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/basic-integration-optional-chaining/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "proposal-optional-chaining", "bugfix-v8-spread-parameters-in-optional-chaining"
+  ]
+}

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

@@ -0,0 +1,5 @@
+var _fn, _a, _a2, _a2$b;
+
+(_fn = fn) === null || _fn === void 0 ? void 0 : _fn(...b, 1);
+(_a = a) === null || _a === void 0 ? void 0 : _a.b(...c, 1);
+(_a2 = a) === null || _a2 === void 0 ? void 0 : (_a2$b = _a2.b) === null || _a2$b === void 0 ? void 0 : _a2$b.call(_a2, ...c, 1);

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/basic/input.mjs

@@ -0,0 +1,7 @@
+fn?.(...b, 1);
+
+a?.b(...c, 1);
+
+a?.b?.(...c, 1);
+
+a.b?.(...c, 1);

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

@@ -0,0 +1,6 @@
+var _fn, _a, _a2, _a2$b, _a$b, _a3;
+
+(_fn = fn) === null || _fn === void 0 ? void 0 : _fn(...b, 1);
+(_a = a) === null || _a === void 0 ? void 0 : _a.b(...c, 1);
+(_a2 = a) === null || _a2 === void 0 ? void 0 : (_a2$b = _a2.b) === null || _a2$b === void 0 ? void 0 : _a2$b.call(_a2, ...c, 1);
+(_a$b = (_a3 = a).b) === null || _a$b === void 0 ? void 0 : _a$b.call(_a3, ...c, 1);

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

@@ -0,0 +1,13 @@
+class C {
+  #m;
+  constructor() {
+    const o = null;
+    const n = this;
+    const p = o?.#m(...c, 1);
+    const q = n?.#m?.(...c, 1);
+    expect(p).toBe(undefined);
+    expect(q).toBe(undefined);
+  }
+}
+
+new C();

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

@@ -0,0 +1,9 @@
+class C {
+    #m;
+    constructor() {
+        const o = null;
+        const n = this;
+        const p = o?.#m(...c, 1);
+        const q = n?.#m?.(...c, 1);
+    }
+}

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

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "proposal-class-properties", "proposal-private-methods", "proposal-optional-chaining", "bugfix-v8-spread-parameters-in-optional-chaining"
+  ]
+}

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

@@ -0,0 +1,18 @@
+var _m = new WeakMap();
+
+class C {
+  constructor() {
+    var _babelHelpers$classPr;
+
+    _m.set(this, {
+      writable: true,
+      value: void 0
+    });
+
+    const o = null;
+    const n = this;
+    const p = o === null || o === void 0 ? void 0 : babelHelpers.classPrivateFieldGet(o, _m).call(o, ...c, 1);
+    const q = n === null || n === void 0 ? void 0 : (_babelHelpers$classPr = babelHelpers.classPrivateFieldGet(n, _m)) === null || _babelHelpers$classPr === void 0 ? void 0 : _babelHelpers$classPr.call(n, ...c, 1);
+  }
+
+}

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

@@ -0,0 +1,13 @@
+class C {
+  #m;
+  constructor() {
+    const o = null;
+    const n = this;
+    const p = o?.#m(...c, 1);
+    const q = n?.#m?.(...c, 1);
+    expect(p).toBe(undefined);
+    expect(q).toBe(undefined);
+  }
+}
+
+new C();

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

@@ -0,0 +1,9 @@
+class C {
+    #m;
+    constructor() {
+        const o = null;
+        const n = this;
+        const p = o?.#m(...c, 1);
+        const q = n?.#m?.(...c, 1);
+    }
+}

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

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "proposal-class-properties", "proposal-private-methods", "bugfix-v8-spread-parameters-in-optional-chaining"
+  ]
+}

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

@@ -0,0 +1,18 @@
+var _m = new WeakMap();
+
+class C {
+  constructor() {
+    var _babelHelpers$classPr;
+
+    _m.set(this, {
+      writable: true,
+      value: void 0
+    });
+
+    const o = null;
+    const n = this;
+    const p = o === null || o === void 0 ? void 0 : babelHelpers.classPrivateFieldGet(o, _m).call(o, ...c, 1);
+    const q = n === null || n === void 0 ? void 0 : (_babelHelpers$classPr = babelHelpers.classPrivateFieldGet(n, _m)) === null || _babelHelpers$classPr === void 0 ? void 0 : _babelHelpers$classPr.call(n, ...c, 1);
+  }
+
+}

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

@@ -0,0 +1,13 @@
+class C {
+    #m;
+    constructor() {
+        const o = null;
+        const n = this;
+        const p = o?.#m(...c, 1);
+        const q = n?.#m?.(...c, 1);
+        expect(p).toBe(undefined);
+        expect(q).toBe(undefined);
+    }
+}
+
+new C;

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

@@ -0,0 +1,9 @@
+class C {
+    #m;
+    constructor() {
+        const o = null;
+        const n = this;
+        const p = o?.#m(...c, 1);
+        const q = n?.#m?.(...c, 1);
+    }
+}

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/basic/class-private/options.json

@@ -0,0 +1,10 @@
+{
+  "minNodeVersion": "14.0.0",
+  "parserOpts": {
+    "plugins": [
+      "classPrivateMethods",
+      "classPrivateProperties",
+      "classProperties"
+    ]
+  }
+}

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

@@ -0,0 +1,13 @@
+class C {
+  #m;
+
+  constructor() {
+    var _n$m;
+
+    const o = null;
+    const n = this;
+    const p = o === null || o === void 0 ? void 0 : o.#m(...c, 1);
+    const q = n === null || n === void 0 ? void 0 : (_n$m = n.#m) === null || _n$m === void 0 ? void 0 : _n$m.call(n, ...c, 1);
+  }
+
+}

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/fixtures/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["bugfix-v8-spread-parameters-in-optional-chaining"]
+}

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/index.js

@@ -0,0 +1,3 @@
+import runner from "@babel/helper-plugin-test-runner";
+
+runner(import.meta.url);

packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/test/util.test.js

@@ -0,0 +1,115 @@
+import { parseSync, traverse } from "@babel/core";
+import { shouldTransform } from "../src/util.ts";
+
+function getPath(input, parserOpts = {}) {
+  let targetPath;
+  traverse(
+    parseSync(input, {
+      parserOpts: {
+        plugins: [
+          "classPrivateMethods",
+          "classPrivateProperties",
+          "classProperties",
+          ...(parserOpts.plugins || []),
+        ],
+        ...parserOpts,
+      },
+      filename: "example.js",
+    }),
+    {
+      "OptionalMemberExpression|OptionalCallExpression"(path) {
+        targetPath = path;
+        path.stop();
+      },
+      noScope: true,
+    },
+  );
+  return targetPath;
+}
+
+describe("shouldTransform", () => {
+  const positiveCases = [
+    "fn?.(...[], 0)",
+    "fn?.(...[], ...[])",
+    "fn?.(0, ...[], ...[])",
+    "a?.b(...[], 0)",
+    "a?.[b](...[], 0)",
+    "a?.b?.(...[], 0)",
+    "fn?.(0, ...[], 0)",
+    "a?.b?.(0, ...[], 0)",
+    "(a?.b)?.(...[], 0)",
+    "a?.b.c?.(...[], 0)",
+    "class C { #c; p = obj?.#c(...[], 0) }",
+    "class C { #c; p = obj.#c?.(...[], 0) }",
+  ];
+
+  const negativeCases = [
+    "a?.b",
+    "fn?.(1)",
+    "fn?.(...[])",
+    "fn?.(1, ...[])",
+    "a?.b(...[])",
+    "a?.()(...[], 1)", // optional call under optional call is not affected
+    "(a?.b)(...[], 1)", // not an optional call
+    "a?.b.c(...[], 1)",
+    "a?.[fn?.(...[], 0)]", // optional chain in property will be handled when traversed
+    "a?.(fn?.(...[], 0))", // optional chain in arguments will be handled when traversed
+    "class C { #c; p = obj?.#c(...[]) }",
+  ];
+
+  const typescriptPositiveCases = [
+    "(a?.(...[], 0) as any)?.b",
+    "(a?.(...[], 0) as any)?.()",
+  ];
+
+  const typescriptNegativeCases = ["(a?.b as any)(...[], 0)"];
+
+  describe("default parser options", () => {
+    test.each(positiveCases)(
+      "shouldTransform(a?.b in %p) should return true",
+      input => {
+        expect(shouldTransform(getPath(input))).toBe(true);
+      },
+    );
+    test.each(negativeCases)(
+      "shouldTransform(a?.b in %p) should return false",
+      input => {
+        expect(shouldTransform(getPath(input))).toBe(false);
+      },
+    );
+  });
+
+  describe("createParenthesizedExpressions", () => {
+    test.each(positiveCases)(
+      "shouldTransform(a?.b in %p with { createParenthesizedExpressions: true }) should return true",
+      input => {
+        const parserOpts = { createParenthesizedExpressions: true };
+        expect(shouldTransform(getPath(input, parserOpts))).toBe(true);
+      },
+    );
+    test.each(negativeCases)(
+      "shouldTransform(a?.b in %p with { createParenthesizedExpressions: true }) should return false",
+      input => {
+        const parserOpts = { createParenthesizedExpressions: true };
+        expect(shouldTransform(getPath(input, parserOpts))).toBe(false);
+      },
+    );
+  });
+
+  describe("plugins: [typescript]", () => {
+    test.each(positiveCases.concat(typescriptPositiveCases))(
+      "shouldTransform(a?.b in %p with { plugins: [typescript] }) should return true",
+      input => {
+        const parserOpts = { plugins: ["typescript"] };
+        expect(shouldTransform(getPath(input, parserOpts))).toBe(true);
+      },
+    );
+    test.each(negativeCases.concat(typescriptNegativeCases))(
+      "shouldTransform(a?.b in %p with { plugins: [typescript] }) should return false",
+      input => {
+        const parserOpts = { plugins: ["typescript"] };
+        expect(shouldTransform(getPath(input, parserOpts))).toBe(false);
+      },
+    );
+  });
+});

packages/babel-plugin-proposal-optional-chaining/src/index.js

@@ -1,13 +1,6 @@
 import { declare } from "@babel/helper-plugin-utils";
-import {
-  isTransparentExprWrapper,
-  skipTransparentExprWrappers,
-} from "@babel/helper-skip-transparent-expression-wrappers";
 import syntaxOptionalChaining from "@babel/plugin-syntax-optional-chaining";
-import { types as t, template } from "@babel/core";
+import { transform } from "./transform";
-import { willPathCastToBoolean, findOutermostTransparentParent } from "./util";
-
-const { ast } = template.expression;
 
 export default declare((api, options) => {
   api.assertVersion(7);
@@ -16,229 +9,16 @@ export default declare((api, options) => {
   const noDocumentAll = api.assumption("noDocumentAll") ?? loose;
   const pureGetters = api.assumption("pureGetters") ?? loose;
 
-  function isSimpleMemberExpression(expression) {
-    expression = skipTransparentExprWrappers(expression);
-    return (
-      t.isIdentifier(expression) ||
-      t.isSuper(expression) ||
-      (t.isMemberExpression(expression) &&
-        !expression.computed &&
-        isSimpleMemberExpression(expression.object))
-    );
-  }
-
-  /**
-   * Test if a given optional chain `path` needs to be memoized
-   * @param {NodePath} path
-   * @returns {boolean}
-   */
-  function needsMemoize(path) {
-    let optionalPath = path;
-    const { scope } = path;
-    while (
-      optionalPath.isOptionalMemberExpression() ||
-      optionalPath.isOptionalCallExpression()
-    ) {
-      const { node } = optionalPath;
-      const childKey = optionalPath.isOptionalMemberExpression()
-        ? "object"
-        : "callee";
-      const childPath = skipTransparentExprWrappers(optionalPath.get(childKey));
-      if (node.optional) {
-        return !scope.isStatic(childPath.node);
-      }
-
-      optionalPath = childPath;
-    }
-  }
-
   return {
     name: "proposal-optional-chaining",
     inherits: syntaxOptionalChaining,
 
     visitor: {
       "OptionalCallExpression|OptionalMemberExpression"(path) {
-        const { scope } = path;
+        transform(path, { noDocumentAll, pureGetters });
-        // maybeWrapped points to the outermost transparent expression wrapper
-        // or the path itself
-        const maybeWrapped = findOutermostTransparentParent(path);
-        const { parentPath } = maybeWrapped;
-        const willReplacementCastToBoolean = willPathCastToBoolean(
-          maybeWrapped,
-        );
-        let isDeleteOperation = false;
-        const parentIsCall =
-          parentPath.isCallExpression({ callee: maybeWrapped.node }) &&
-          // note that the first condition must implies that `path.optional` is `true`,
-          // otherwise the parentPath should be an OptionalCallExpressioin
-          path.isOptionalMemberExpression();
-
-        const optionals = [];
-
-        let optionalPath = path;
-        // Replace `function (a, x = a.b?.c) {}` to `function (a, x = (() => a.b?.c)() ){}`
-        // so the temporary variable can be injected in correct scope
-        if (scope.path.isPattern() && needsMemoize(optionalPath)) {
-          path.replaceWith(template.ast`(() => ${path.node})()`);
-          // The injected optional chain will be queued and eventually transformed when visited
-          return;
-        }
-        while (
-          optionalPath.isOptionalMemberExpression() ||
-          optionalPath.isOptionalCallExpression()
-        ) {
-          const { node } = optionalPath;
-          if (node.optional) {
-            optionals.push(node);
-          }
-
-          if (optionalPath.isOptionalMemberExpression()) {
-            optionalPath.node.type = "MemberExpression";
-            optionalPath = skipTransparentExprWrappers(
-              optionalPath.get("object"),
-            );
-          } else if (optionalPath.isOptionalCallExpression()) {
-            optionalPath.node.type = "CallExpression";
-            optionalPath = skipTransparentExprWrappers(
-              optionalPath.get("callee"),
-            );
-          }
-        }
-
-        let replacementPath = path;
-        if (parentPath.isUnaryExpression({ operator: "delete" })) {
-          replacementPath = parentPath;
-          isDeleteOperation = true;
-        }
-        for (let i = optionals.length - 1; i >= 0; i--) {
-          const node = optionals[i];
-
-          const isCall = t.isCallExpression(node);
-          const replaceKey = isCall ? "callee" : "object";
-
-          const chainWithTypes = node[replaceKey];
-          let chain = chainWithTypes;
-
-          while (isTransparentExprWrapper(chain)) {
-            chain = chain.expression;
-          }
-
-          let ref;
-          let check;
-          if (isCall && t.isIdentifier(chain, { name: "eval" })) {
-            check = ref = chain;
-            // `eval?.()` is an indirect eval call transformed to `(0,eval)()`
-            node[replaceKey] = t.sequenceExpression([t.numericLiteral(0), ref]);
-          } else if (pureGetters && isCall && isSimpleMemberExpression(chain)) {
-            // If we assume getters are pure (avoiding a Function#call) and we are at the call,
-            // we can avoid a needless memoize. We only do this if the callee is a simple member
-            // expression, to avoid multiple calls to nested call expressions.
-            check = ref = chainWithTypes;
-          } else {
-            ref = scope.maybeGenerateMemoised(chain);
-            if (ref) {
-              check = t.assignmentExpression(
-                "=",
-                t.cloneNode(ref),
-                // Here `chainWithTypes` MUST NOT be cloned because it could be
-                // updated when generating the memoised context of a call
-                // expression
-                chainWithTypes,
-              );
-
-              node[replaceKey] = ref;
-            } else {
-              check = ref = chainWithTypes;
-            }
-          }
-
-          // Ensure call expressions have the proper `this`
-          // `foo.bar()` has context `foo`.
-          if (isCall && t.isMemberExpression(chain)) {
-            if (pureGetters && isSimpleMemberExpression(chain)) {
-              // To avoid a Function#call, we can instead re-grab the property from the context object.
-              // `a.?b.?()` translates roughly to `_a.b != null && _a.b()`
-              node.callee = chainWithTypes;
-            } else {
-              // Otherwise, we need to memoize the context object, and change the call into a Function#call.
-              // `a.?b.?()` translates roughly to `(_b = _a.b) != null && _b.call(_a)`
-              const { object } = chain;
-              let context = scope.maybeGenerateMemoised(object);
-              if (context) {
-                chain.object = t.assignmentExpression("=", context, object);
-              } else if (t.isSuper(object)) {
-                context = t.thisExpression();
-              } else {
-                context = object;
-              }
-
-              node.arguments.unshift(t.cloneNode(context));
-              node.callee = t.memberExpression(
-                node.callee,
-                t.identifier("call"),
-              );
-            }
-          }
-          let replacement = replacementPath.node;
-          // Ensure (a?.b)() has proper `this`
-          // The `parentIsCall` is constant within loop, we should check i === 0
-          // to ensure that it is only applied to the first optional chain element
-          // i.e. `?.b` in `(a?.b.c)()`
-          if (i === 0 && parentIsCall) {
-            // `(a?.b)()` to `(a == null ? undefined : a.b.bind(a))()`
-            const object = skipTransparentExprWrappers(
-              replacementPath.get("object"),
-            ).node;
-            let baseRef;
-            if (!pureGetters || !isSimpleMemberExpression(object)) {
-              // memoize the context object when getters are not always pure
-              // or the object is not a simple member expression
-              // `(a?.b.c)()` to `(a == null ? undefined : (_a$b = a.b).c.bind(_a$b))()`
-              baseRef = scope.maybeGenerateMemoised(object);
-              if (baseRef) {
-                replacement.object = t.assignmentExpression(
-                  "=",
-                  baseRef,
-                  object,
-                );
-              }
-            }
-            replacement = t.callExpression(
-              t.memberExpression(replacement, t.identifier("bind")),
-              [t.cloneNode(baseRef ?? object)],
-            );
-          }
-
-          if (willReplacementCastToBoolean) {
-            // `if (a?.b) {}` transformed to `if (a != null && a.b) {}`
-            // we don't need to return `void 0` because the returned value will
-            // eveutally cast to boolean.
-            const nonNullishCheck = noDocumentAll
-              ? ast`${t.cloneNode(check)} != null`
-              : ast`
-            ${t.cloneNode(check)} !== null && ${t.cloneNode(ref)} !== void 0`;
-            replacementPath.replaceWith(
-              t.logicalExpression("&&", nonNullishCheck, replacement),
-            );
-            replacementPath = skipTransparentExprWrappers(
-              replacementPath.get("right"),
-            );
-          } else {
-            const nullishCheck = noDocumentAll
-              ? ast`${t.cloneNode(check)} == null`
-              : ast`
-            ${t.cloneNode(check)} === null || ${t.cloneNode(ref)} === void 0`;
-
-            const returnValue = isDeleteOperation ? ast`true` : ast`void 0`;
-            replacementPath.replaceWith(
-              t.conditionalExpression(nullishCheck, returnValue, replacement),
-            );
-            replacementPath = skipTransparentExprWrappers(
-              replacementPath.get("alternate"),
-            );
-          }
-        }
       },
     },
   };
 });
+
+export { transform };

packages/babel-plugin-proposal-optional-chaining/src/transform.js

@@ -0,0 +1,219 @@
+import { types as t, template } from "@babel/core";
+import {
+  isTransparentExprWrapper,
+  skipTransparentExprWrappers,
+} from "@babel/helper-skip-transparent-expression-wrappers";
+import { willPathCastToBoolean, findOutermostTransparentParent } from "./util";
+
+const { ast } = template.expression;
+
+function isSimpleMemberExpression(expression) {
+  expression = skipTransparentExprWrappers(expression);
+  return (
+    t.isIdentifier(expression) ||
+    t.isSuper(expression) ||
+    (t.isMemberExpression(expression) &&
+      !expression.computed &&
+      isSimpleMemberExpression(expression.object))
+  );
+}
+
+/**
+ * Test if a given optional chain `path` needs to be memoized
+ * @param {NodePath} path
+ * @returns {boolean}
+ */
+function needsMemoize(path) {
+  let optionalPath = path;
+  const { scope } = path;
+  while (
+    optionalPath.isOptionalMemberExpression() ||
+    optionalPath.isOptionalCallExpression()
+  ) {
+    const { node } = optionalPath;
+    const childKey = optionalPath.isOptionalMemberExpression()
+      ? "object"
+      : "callee";
+    const childPath = skipTransparentExprWrappers(optionalPath.get(childKey));
+    if (node.optional) {
+      return !scope.isStatic(childPath.node);
+    }
+
+    optionalPath = childPath;
+  }
+}
+
+export function transform(
+  path: NodePath<t.OptionalCallExpression | t.OptionalMemberExpression>,
+  {
+    pureGetters,
+    noDocumentAll,
+  }: { pureGetters: boolean, noDocumentAll: boolean },
+) {
+  const { scope } = path;
+  // maybeWrapped points to the outermost transparent expression wrapper
+  // or the path itself
+  const maybeWrapped = findOutermostTransparentParent(path);
+  const { parentPath } = maybeWrapped;
+  const willReplacementCastToBoolean = willPathCastToBoolean(maybeWrapped);
+  let isDeleteOperation = false;
+  const parentIsCall =
+    parentPath.isCallExpression({ callee: maybeWrapped.node }) &&
+    // note that the first condition must implies that `path.optional` is `true`,
+    // otherwise the parentPath should be an OptionalCallExpression
+    path.isOptionalMemberExpression();
+
+  const optionals = [];
+
+  let optionalPath = path;
+  // Replace `function (a, x = a.b?.c) {}` to `function (a, x = (() => a.b?.c)() ){}`
+  // so the temporary variable can be injected in correct scope
+  if (scope.path.isPattern() && needsMemoize(optionalPath)) {
+    path.replaceWith(template.ast`(() => ${path.node})()`);
+    // The injected optional chain will be queued and eventually transformed when visited
+    return;
+  }
+  while (
+    optionalPath.isOptionalMemberExpression() ||
+    optionalPath.isOptionalCallExpression()
+  ) {
+    const { node } = optionalPath;
+    if (node.optional) {
+      optionals.push(node);
+    }
+
+    if (optionalPath.isOptionalMemberExpression()) {
+      optionalPath.node.type = "MemberExpression";
+      optionalPath = skipTransparentExprWrappers(optionalPath.get("object"));
+    } else if (optionalPath.isOptionalCallExpression()) {
+      optionalPath.node.type = "CallExpression";
+      optionalPath = skipTransparentExprWrappers(optionalPath.get("callee"));
+    }
+  }
+
+  let replacementPath = path;
+  if (parentPath.isUnaryExpression({ operator: "delete" })) {
+    replacementPath = parentPath;
+    isDeleteOperation = true;
+  }
+  for (let i = optionals.length - 1; i >= 0; i--) {
+    const node = optionals[i];
+
+    const isCall = t.isCallExpression(node);
+    const replaceKey = isCall ? "callee" : "object";
+
+    const chainWithTypes = node[replaceKey];
+    let chain = chainWithTypes;
+
+    while (isTransparentExprWrapper(chain)) {
+      chain = chain.expression;
+    }
+
+    let ref;
+    let check;
+    if (isCall && t.isIdentifier(chain, { name: "eval" })) {
+      check = ref = chain;
+      // `eval?.()` is an indirect eval call transformed to `(0,eval)()`
+      node[replaceKey] = t.sequenceExpression([t.numericLiteral(0), ref]);
+    } else if (pureGetters && isCall && isSimpleMemberExpression(chain)) {
+      // If we assume getters are pure (avoiding a Function#call) and we are at the call,
+      // we can avoid a needless memoize. We only do this if the callee is a simple member
+      // expression, to avoid multiple calls to nested call expressions.
+      check = ref = chainWithTypes;
+    } else {
+      ref = scope.maybeGenerateMemoised(chain);
+      if (ref) {
+        check = t.assignmentExpression(
+          "=",
+          t.cloneNode(ref),
+          // Here `chainWithTypes` MUST NOT be cloned because it could be
+          // updated when generating the memoised context of a call
+          // expression
+          chainWithTypes,
+        );
+
+        node[replaceKey] = ref;
+      } else {
+        check = ref = chainWithTypes;
+      }
+    }
+
+    // Ensure call expressions have the proper `this`
+    // `foo.bar()` has context `foo`.
+    if (isCall && t.isMemberExpression(chain)) {
+      if (pureGetters && isSimpleMemberExpression(chain)) {
+        // To avoid a Function#call, we can instead re-grab the property from the context object.
+        // `a.?b.?()` translates roughly to `_a.b != null && _a.b()`
+        node.callee = chainWithTypes;
+      } else {
+        // Otherwise, we need to memoize the context object, and change the call into a Function#call.
+        // `a.?b.?()` translates roughly to `(_b = _a.b) != null && _b.call(_a)`
+        const { object } = chain;
+        let context = scope.maybeGenerateMemoised(object);
+        if (context) {
+          chain.object = t.assignmentExpression("=", context, object);
+        } else if (t.isSuper(object)) {
+          context = t.thisExpression();
+        } else {
+          context = object;
+        }
+
+        node.arguments.unshift(t.cloneNode(context));
+        node.callee = t.memberExpression(node.callee, t.identifier("call"));
+      }
+    }
+    let replacement = replacementPath.node;
+    // Ensure (a?.b)() has proper `this`
+    // The `parentIsCall` is constant within loop, we should check i === 0
+    // to ensure that it is only applied to the first optional chain element
+    // i.e. `?.b` in `(a?.b.c)()`
+    if (i === 0 && parentIsCall) {
+      // `(a?.b)()` to `(a == null ? undefined : a.b.bind(a))()`
+      const object = skipTransparentExprWrappers(replacementPath.get("object"))
+        .node;
+      let baseRef;
+      if (!pureGetters || !isSimpleMemberExpression(object)) {
+        // memoize the context object when getters are not always pure
+        // or the object is not a simple member expression
+        // `(a?.b.c)()` to `(a == null ? undefined : (_a$b = a.b).c.bind(_a$b))()`
+        baseRef = scope.maybeGenerateMemoised(object);
+        if (baseRef) {
+          replacement.object = t.assignmentExpression("=", baseRef, object);
+        }
+      }
+      replacement = t.callExpression(
+        t.memberExpression(replacement, t.identifier("bind")),
+        [t.cloneNode(baseRef ?? object)],
+      );
+    }
+
+    if (willReplacementCastToBoolean) {
+      // `if (a?.b) {}` transformed to `if (a != null && a.b) {}`
+      // we don't need to return `void 0` because the returned value will
+      // eveutally cast to boolean.
+      const nonNullishCheck = noDocumentAll
+        ? ast`${t.cloneNode(check)} != null`
+        : ast`
+            ${t.cloneNode(check)} !== null && ${t.cloneNode(ref)} !== void 0`;
+      replacementPath.replaceWith(
+        t.logicalExpression("&&", nonNullishCheck, replacement),
+      );
+      replacementPath = skipTransparentExprWrappers(
+        replacementPath.get("right"),
+      );
+    } else {
+      const nullishCheck = noDocumentAll
+        ? ast`${t.cloneNode(check)} == null`
+        : ast`
+            ${t.cloneNode(check)} === null || ${t.cloneNode(ref)} === void 0`;
+
+      const returnValue = isDeleteOperation ? ast`true` : ast`void 0`;
+      replacementPath.replaceWith(
+        t.conditionalExpression(nullishCheck, returnValue, replacement),
+      );
+      replacementPath = skipTransparentExprWrappers(
+        replacementPath.get("alternate"),
+      );
+    }
+  }
+}

packages/babel-preset-env/package.json

@@ -20,6 +20,7 @@
     "@babel/helper-compilation-targets": "workspace:^7.13.10",
     "@babel/helper-plugin-utils": "workspace:^7.13.0",
     "@babel/helper-validator-option": "workspace:^7.12.17",
+    "@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining": "workspace:^7.13.8",
     "@babel/plugin-proposal-async-generator-functions": "workspace:^7.13.8",
     "@babel/plugin-proposal-class-properties": "workspace:^7.13.0",
     "@babel/plugin-proposal-dynamic-import": "workspace:^7.13.8",

packages/babel-preset-env/src/available-plugins.js

@@ -65,6 +65,7 @@ import bugfixEdgeFunctionName from "@babel/preset-modules/lib/plugins/transform-
 import bugfixTaggedTemplateCaching from "@babel/preset-modules/lib/plugins/transform-tagged-template-caching";
 import bugfixSafariBlockShadowing from "@babel/preset-modules/lib/plugins/transform-safari-block-shadowing";
 import bugfixSafariForShadowing from "@babel/preset-modules/lib/plugins/transform-safari-for-shadowing";
+import bugfixV8SpreadParametersInOptionalChaining from "@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining";
 
 export default {
   "bugfix/transform-async-arrows-in-class": bugfixAsyncArrowsInClass,
@@ -73,6 +74,7 @@ export default {
   "bugfix/transform-safari-block-shadowing": bugfixSafariBlockShadowing,
   "bugfix/transform-safari-for-shadowing": bugfixSafariForShadowing,
   "bugfix/transform-tagged-template-caching": bugfixTaggedTemplateCaching,
+  "bugfix/transform-v8-spread-parameters-in-optional-chaining": bugfixV8SpreadParametersInOptionalChaining,
   "proposal-async-generator-functions": proposalAsyncGeneratorFunctions,
   "proposal-class-properties": proposalClassProperties,
   "proposal-dynamic-import": proposalDynamicImport,

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89-no-bugfixes/input.js

@@ -0,0 +1,3 @@
+fn?.();
+
+fn?.(...[], 0);

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89-no-bugfixes/options.json

@@ -0,0 +1,12 @@
+{
+  "validateLogs": true,
+  "presets": [
+    ["env", {
+      "debug": true,
+      "bugfixes": false,
+      "targets": {
+        "chrome": "89"
+      }
+    }]
+  ]
+}

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89-no-bugfixes/output.js

@@ -0,0 +1,4 @@
+var _fn, _fn2;
+
+(_fn = fn) === null || _fn === void 0 ? void 0 : _fn();
+(_fn2 = fn) === null || _fn2 === void 0 ? void 0 : _fn2(...[], 0);

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89-no-bugfixes/stdout.txt

@@ -0,0 +1,22 @@
+@babel/preset-env: `DEBUG` option
+
+Using targets:
+{
+  "chrome": "89"
+}
+
+Using modules transform: auto
+
+Using plugins:
+  syntax-numeric-separator { "chrome":"89" }
+  syntax-nullish-coalescing-operator { "chrome":"89" }
+  proposal-optional-chaining { "chrome":"89" }
+  syntax-json-strings { "chrome":"89" }
+  syntax-optional-catch-binding { "chrome":"89" }
+  syntax-async-generators { "chrome":"89" }
+  syntax-object-rest-spread { "chrome":"89" }
+  transform-modules-commonjs { "chrome":"89" }
+  proposal-dynamic-import { "chrome":"89" }
+  proposal-export-namespace-from {}
+
+Using polyfills: No polyfills were added, since the `useBuiltIns` option was not set.

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89/input.js

@@ -0,0 +1,3 @@
+fn?.();
+
+fn?.(...[], 0);

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89/options.json

@@ -0,0 +1,12 @@
+{
+  "validateLogs": true,
+  "presets": [
+    ["env", {
+      "debug": true,
+      "bugfixes": true,
+      "targets": {
+        "chrome": "89"
+      }
+    }]
+  ]
+}

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89/output.js

@@ -0,0 +1,4 @@
+var _fn;
+
+fn?.();
+(_fn = fn) === null || _fn === void 0 ? void 0 : _fn(...[], 0);

packages/babel-preset-env/test/fixtures/bugfixes/v8-spread-parameters-in-optional-chaining-chrome-89/stdout.txt

@@ -0,0 +1,23 @@
+@babel/preset-env: `DEBUG` option
+
+Using targets:
+{
+  "chrome": "89"
+}
+
+Using modules transform: auto
+
+Using plugins:
+  syntax-numeric-separator { "chrome":"89" }
+  syntax-nullish-coalescing-operator { "chrome":"89" }
+  syntax-optional-chaining { "chrome":"89" }
+  syntax-json-strings { "chrome":"89" }
+  syntax-optional-catch-binding { "chrome":"89" }
+  syntax-async-generators { "chrome":"89" }
+  syntax-object-rest-spread { "chrome":"89" }
+  bugfix/transform-v8-spread-parameters-in-optional-chaining { "chrome":"89" }
+  transform-modules-commonjs { "chrome":"89" }
+  proposal-dynamic-import { "chrome":"89" }
+  proposal-export-namespace-from {}
+
+Using polyfills: No polyfills were added, since the `useBuiltIns` option was not set.

yarn.lock

@@ -973,6 +973,21 @@ __metadata:
   languageName: unknown
   linkType: soft
 
+"@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining@workspace:^7.13.8, @babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining@workspace:packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining":
+  version: 0.0.0-use.local
+  resolution: "@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining@workspace:packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining"
+  dependencies:
+    "@babel/core": "workspace:*"
+    "@babel/helper-plugin-test-runner": "workspace:*"
+    "@babel/helper-plugin-utils": "workspace:^7.13.0"
+    "@babel/helper-skip-transparent-expression-wrappers": "workspace:^7.12.1"
+    "@babel/plugin-proposal-optional-chaining": "workspace:^7.13.8"
+    "@babel/traverse": "workspace:*"
+  peerDependencies:
+    "@babel/core": ^7.13.0
+  languageName: unknown
+  linkType: soft
+
 "@babel/plugin-codemod-object-assign-to-object-spread@workspace:codemods/babel-plugin-codemod-object-assign-to-object-spread":
   version: 0.0.0-use.local
   resolution: "@babel/plugin-codemod-object-assign-to-object-spread@workspace:codemods/babel-plugin-codemod-object-assign-to-object-spread"
@@ -3068,6 +3083,7 @@ __metadata:
     "@babel/helper-plugin-test-runner": "workspace:*"
     "@babel/helper-plugin-utils": "workspace:^7.13.0"
     "@babel/helper-validator-option": "workspace:^7.12.17"
+    "@babel/plugin-bugfix-v8-spread-parameters-in-optional-chaining": "workspace:^7.13.8"
     "@babel/plugin-proposal-async-generator-functions": "workspace:^7.13.8"
     "@babel/plugin-proposal-class-properties": "workspace:^7.13.0"
     "@babel/plugin-proposal-dynamic-import": "workspace:^7.13.8"