improve helper-create-class-features typings (#14530)

packages/babel-core/src/config/validation/plugins.ts

@@ -13,8 +13,8 @@ import type {
 } from "./option-assertions";
 import type { ParserOptions } from "@babel/parser";
 import type { Visitor } from "@babel/traverse";
-import type PluginPass from "../../transformation/plugin-pass";
 import type { ValidatedOptions } from "./options";
+import type { File, PluginPass } from "../../..";
 
 // Note: The casts here are just meant to be static assertions to make sure
 // that the assertion functions actually assert that the value's type matches
@@ -78,14 +78,14 @@ type VisitorHandler =
       exit?: Function;
     };
 
-export type PluginObject<S = PluginPass> = {
+export type PluginObject<S extends PluginPass = PluginPass> = {
   name?: string;
   manipulateOptions?: (
     options: ValidatedOptions,
     parserOpts: ParserOptions,
   ) => void;
-  pre?: Function;
-  post?: Function;
+  pre?: (this: S, file: File) => void;
+  post?: (this: S, file: File) => void;
   inherits?: Function;
   visitor?: Visitor<S>;
   parserOverride?: Function;

packages/babel-core/src/transformation/index.ts

@@ -3,7 +3,7 @@ import type * as t from "@babel/types";
 type SourceMap = any;
 import type { Handler } from "gensync";
 
-import type { ResolvedConfig, PluginPasses } from "../config";
+import type { ResolvedConfig, Plugin, PluginPasses } from "../config";
 
 import PluginPass from "./plugin-pass";
 import loadBlockHoistPlugin from "./block-hoist-plugin";
@@ -79,7 +79,7 @@ export function* run(
 
 function* transformFile(file: File, pluginPasses: PluginPasses): Handler<void> {
   for (const pluginPairs of pluginPasses) {
-    const passPairs = [];
+    const passPairs: [Plugin, PluginPass][] = [];
     const passes = [];
     const visitors = [];
 

packages/babel-helper-create-class-features-plugin/src/decorators.ts

@@ -40,51 +40,70 @@ function takeDecorators(node: Decorable) {
   return result;
 }
 
-function getKey(node) {
+type AcceptedElement = Exclude<ClassElement, t.TSIndexSignature>;
+type SupportedElement = Exclude<
+  AcceptedElement,
+  | t.ClassPrivateMethod
+  | t.ClassPrivateProperty
+  | t.ClassAccessorProperty
+  | t.StaticBlock
+>;
+
+function getKey(node: SupportedElement) {
   if (node.computed) {
     return node.key;
   } else if (t.isIdentifier(node.key)) {
     return t.stringLiteral(node.key.name);
   } else {
-    return t.stringLiteral(String(node.key.value));
+    return t.stringLiteral(
+      String(
+        // A non-identifier non-computed key
+        (node.key as t.StringLiteral | t.NumericLiteral | t.BigIntLiteral)
+          .value,
+      ),
+    );
   }
 }
 
-// NOTE: This function can be easily bound as .bind(file, classRef, superRef)
-//       to make it easier to use it in a loop.
 function extractElementDescriptor(
-  this: File,
+  file: File,
   classRef: t.Identifier,
   superRef: t.Identifier,
-  path: ClassElementPath,
+  path: NodePath<AcceptedElement>,
 ) {
-  const { node, scope } = path;
   const isMethod = path.isClassMethod();
-
   if (path.isPrivate()) {
     throw path.buildCodeFrameError(
       `Private ${
         isMethod ? "methods" : "fields"
       } in decorated classes are not supported yet.`,
     );
   }
+  if (path.node.type === "ClassAccessorProperty") {
+    throw path.buildCodeFrameError(
+      `Accessor properties are not supported in 2018-09 decorator transform, please specify { "version": "2021-12" } instead.`,
+    );
+  }
+  if (path.node.type === "StaticBlock") {
+    throw path.buildCodeFrameError(
+      `Static blocks are not supported in 2018-09 decorator transform, please specify { "version": "2021-12" } instead.`,
+    );
+  }
+
+  const { node, scope } = path as NodePath<SupportedElement>;
 
   new ReplaceSupers({
     methodPath: path,
     objectRef: classRef,
     superRef,
-    file: this,
+    file,
     refToPreserve: classRef,
   }).replace();
 
   const properties: t.ObjectExpression["properties"] = [
     prop("kind", t.stringLiteral(t.isClassMethod(node) ? node.kind : "field")),
     prop("decorators", takeDecorators(node as Decorable)),
-    prop(
-      "static",
-      // @ts-expect-error: TS doesn't infer that node is not a StaticBlock
-      !t.isStaticBlock?.(node) && node.static && t.booleanLiteral(true),
-    ),
+    prop("static", node.static && t.booleanLiteral(true)),
     prop("key", getKey(node)),
   ].filter(Boolean);
 
@@ -146,9 +165,20 @@ export function buildDecoratedClass(
   const classDecorators = takeDecorators(node);
   const definitions = t.arrayExpression(
     elements
-      // @ts-expect-error Ignore TypeScript's abstract methods (see #10514)
-      .filter(element => !element.node.abstract)
-      .map(extractElementDescriptor.bind(file, node.id, superId)),
+      .filter(
+        element =>
+          // @ts-expect-error Ignore TypeScript's abstract methods (see #10514)
+          !element.node.abstract && element.node.type !== "TSIndexSignature",
+      )
+      .map(path =>
+        extractElementDescriptor(
+          file,
+          node.id,
+          superId,
+          // @ts-expect-error TS can not exclude TSIndexSignature
+          path,
+        ),
+      ),
   );
 
   const wrapperCall = template.expression.ast`

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

@@ -850,17 +850,19 @@ function buildPrivateMethodDeclaration(
   );
 }
 
-const thisContextVisitor = traverse.visitors.merge<{
+type ReplaceThisState = {
   classRef: t.Identifier;
   needsClassRef: boolean;
-  innerBinding: t.Identifier;
-}>([
+  innerBinding: t.Identifier | null;
+};
+
+const thisContextVisitor = traverse.visitors.merge<ReplaceThisState>([
   {
     ThisExpression(path, state) {
       state.needsClassRef = true;
       path.replaceWith(t.cloneNode(state.classRef));
     },
-    MetaProperty(path: NodePath<t.MetaProperty>) {
+    MetaProperty(path) {
       const meta = path.get("meta");
       const property = path.get("property");
       const { scope } = path;
@@ -877,8 +879,8 @@ const thisContextVisitor = traverse.visitors.merge<{
   environmentVisitor,
 ]);
 
-const innerReferencesVisitor = {
-  ReferencedIdentifier(path: NodePath<t.Identifier>, state) {
+const innerReferencesVisitor: Visitor<ReplaceThisState> = {
+  ReferencedIdentifier(path, state) {
     if (
       path.scope.bindingIdentifierEquals(path.node.name, state.innerBinding)
     ) {
@@ -895,9 +897,9 @@ function replaceThisContext(
   file: File,
   isStaticBlock: boolean,
   constantSuper: boolean,
-  innerBindingRef: t.Identifier,
+  innerBindingRef: t.Identifier | null,
 ) {
-  const state = {
+  const state: ReplaceThisState = {
     classRef: ref,
     needsClassRef: false,
     innerBinding: innerBindingRef,
@@ -922,7 +924,12 @@ function replaceThisContext(
     path.traverse(thisContextVisitor, state);
   }
 
-  if (state.classRef?.name && state.classRef.name !== innerBindingRef?.name) {
+  // todo: use innerBinding.referencePaths to avoid full traversal
+  if (
+    innerBindingRef != null &&
+    state.classRef?.name &&
+    state.classRef.name !== innerBindingRef?.name
+  ) {
     path.traverse(innerReferencesVisitor, state);
   }
 

packages/babel-helper-create-class-features-plugin/src/index.ts

@@ -1,5 +1,5 @@
 import { types as t } from "@babel/core";
-import type { File, PluginAPI, PluginObject } from "@babel/core";
+import type { PluginAPI, PluginObject } from "@babel/core";
 import type { NodePath } from "@babel/traverse";
 import nameFunction from "@babel/helper-function-name";
 import splitExportDeclaration from "@babel/helper-split-export-declaration";
@@ -45,7 +45,7 @@ export function createClassFeaturePlugin({
   // @ts-ignore TODO(Babel 8): Remove the default value
   api = { assumption: () => void 0 },
   inherits,
-}: Options) {
+}: Options): PluginObject {
   const setPublicClassFields = api.assumption("setPublicClassFields");
   const privateFieldsAsProperties = api.assumption("privateFieldsAsProperties");
   const constantSuper = api.assumption("constantSuper");
@@ -81,23 +81,23 @@ export function createClassFeaturePlugin({
     manipulateOptions,
     inherits,
 
-    pre() {
-      enableFeature(this.file, feature, loose);
+    pre(file) {
+      enableFeature(file, feature, loose);
 
-      if (!this.file.get(versionKey) || this.file.get(versionKey) < version) {
-        this.file.set(versionKey, version);
+      if (!file.get(versionKey) || file.get(versionKey) < version) {
+        file.set(versionKey, version);
       }
     },
 
     visitor: {
-      Class(path: NodePath<t.Class>, state: File) {
-        if (this.file.get(versionKey) !== version) return;
+      Class(path, { file }) {
+        if (file.get(versionKey) !== version) return;
 
-        if (!shouldTransform(path, this.file)) return;
+        if (!shouldTransform(path, file)) return;
 
         if (path.isClassDeclaration()) assertFieldTransformed(path);
 
-        const loose = isLoose(this.file, feature);
+        const loose = isLoose(file, feature);
 
         let constructor: NodePath<t.ClassMethod>;
         const isDecorated = hasDecorators(path.node);
@@ -186,7 +186,7 @@ export function createClassFeaturePlugin({
         const privateNamesNodes = buildPrivateNamesNodes(
           privateNamesMap,
           (privateFieldsAsProperties ?? loose) as boolean,
-          state,
+          file,
         );
 
         transformPrivateNamesUsage(
@@ -198,7 +198,7 @@ export function createClassFeaturePlugin({
             noDocumentAll,
             innerBinding,
           },
-          state,
+          file,
         );
 
         let keysNodes: t.Statement[],
@@ -213,17 +213,17 @@ export function createClassFeaturePlugin({
             ref,
             path,
             elements,
-            this.file,
+            file,
           ));
         } else {
-          keysNodes = extractComputedKeys(ref, path, computedPaths, this.file);
+          keysNodes = extractComputedKeys(path, computedPaths, file);
           ({ staticNodes, pureStaticNodes, instanceNodes, wrapClass } =
             buildFieldsInitNodes(
               ref,
               path.node.superClass,
               props,
               privateNamesMap,
-              state,
+              file,
               (setPublicClassFields ?? loose) as boolean,
               (privateFieldsAsProperties ?? loose) as boolean,
               (constantSuper ?? loose) as boolean,
@@ -260,8 +260,8 @@ export function createClassFeaturePlugin({
         }
       },
 
-      ExportDefaultDeclaration(path: NodePath<t.ExportDefaultDeclaration>) {
-        if (this.file.get(versionKey) !== version) return;
+      ExportDefaultDeclaration(path, { file }) {
+        if (file.get(versionKey) !== version) return;
 
         const decl = path.get("declaration");
 

packages/babel-helper-create-class-features-plugin/src/misc.ts

@@ -5,7 +5,7 @@ import environmentVisitor from "@babel/helper-environment-visitor";
 
 const findBareSupers = traverse.visitors.merge<NodePath<t.CallExpression>[]>([
   {
-    Super(path: NodePath<t.Super>) {
+    Super(path) {
       const { node, parentPath } = path;
       if (parentPath.isCallExpression({ callee: node })) {
         this.push(parentPath);
@@ -15,24 +15,29 @@ const findBareSupers = traverse.visitors.merge<NodePath<t.CallExpression>[]>([
   environmentVisitor,
 ]);
 
-const referenceVisitor = {
-  "TSTypeAnnotation|TypeAnnotation"(path: NodePath) {
+const referenceVisitor: Visitor<{ scope: Scope }> = {
+  "TSTypeAnnotation|TypeAnnotation"(
+    path: NodePath<t.TSTypeAnnotation | t.TypeAnnotation>,
+  ) {
     path.skip();
   },
 
-  ReferencedIdentifier(path: NodePath<t.Identifier>) {
-    if (this.scope.hasOwnBinding(path.node.name)) {
-      this.scope.rename(path.node.name);
+  ReferencedIdentifier(path: NodePath<t.Identifier>, { scope }) {
+    if (scope.hasOwnBinding(path.node.name)) {
+      scope.rename(path.node.name);
       path.skip();
     }
   },
 };
+
+type HandleClassTDZState = {
+  classBinding: Binding;
+  file: File;
+};
+
 function handleClassTDZ(
   path: NodePath<t.Identifier>,
-  state: {
-    classBinding: Binding;
-    file: File;
-  },
+  state: HandleClassTDZState,
 ) {
   if (
     state.classBinding &&
@@ -48,7 +53,7 @@ function handleClassTDZ(
   }
 }
 
-const classFieldDefinitionEvaluationTDZVisitor = {
+const classFieldDefinitionEvaluationTDZVisitor: Visitor<HandleClassTDZState> = {
   ReferencedIdentifier: handleClassTDZ,
 };
 
@@ -89,7 +94,7 @@ export function injectInitialization(
   }
 
   if (isDerived) {
-    const bareSupers = [];
+    const bareSupers: NodePath<t.CallExpression>[] = [];
     constructor.traverse(findBareSupers, bareSupers);
     let isFirst = true;
     for (const bareSuper of bareSupers) {
@@ -106,12 +111,11 @@ export function injectInitialization(
 }
 
 export function extractComputedKeys(
-  ref: t.Identifier,
   path: NodePath<t.Class>,
   computedPaths: NodePath<t.ClassProperty | t.ClassMethod>[],
   file: File,
 ) {
-  const declarations: t.Statement[] = [];
+  const declarations: t.ExpressionStatement[] = [];
   const state = {
     classBinding: path.node.id && path.scope.getBinding(path.node.id.name),
     file,

packages/babel-plugin-proposal-decorators/test/fixtures/2018-09-integrations/class-accessor-property/input.js

@@ -0,0 +1,3 @@
+@f class C {
+  accessor x;
+}