Add typings to create-class-features-plugin helper (#13570)

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>
babel · Aug 2, 2021 · 1960f23 · 1960f23
1 parent b3ab476
commit 1960f23
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Showing 10 changed files with 576 additions and 328 deletions.
diff --git a/packages/babel-helper-create-class-features-plugin/src/decorators.ts b/packages/babel-helper-create-class-features-plugin/src/decorators.ts
@@ -1,21 +1,26 @@
 import { types as t, template } from "@babel/core";
+import type { File } from "@babel/core";
+import type { NodePath } from "@babel/traverse";
 import ReplaceSupers from "@babel/helper-replace-supers";
 import nameFunction from "@babel/helper-function-name";
 
-export function hasOwnDecorators(node) {
+type Decorable = Extract<t.Node, { decorators?: t.Decorator[] | null }>;
+
+export function hasOwnDecorators(node: t.Node) {
+  // @ts-expect-error(flow->ts) TODO: maybe we could add t.isDecoratable to make ts happy
   return !!(node.decorators && node.decorators.length);
 }
 
-export function hasDecorators(node) {
+export function hasDecorators(node: t.Class) {
   return hasOwnDecorators(node) || node.body.body.some(hasOwnDecorators);
 }
 
-function prop(key, value) {
+function prop(key: string, value?: t.Expression) {
   if (!value) return null;
   return t.objectProperty(t.identifier(key), value);
 }
 
-function method(key, body) {
+function method(key: string, body: t.Statement[]) {
   return t.objectMethod(
     "method",
     t.identifier(key),
@@ -24,8 +29,8 @@ function method(key, body) {
   );
 }
 
-function takeDecorators(node) {
-  let result;
+function takeDecorators(node: Decorable) {
+  let result: t.ArrayExpression | undefined;
   if (node.decorators && node.decorators.length > 0) {
     result = t.arrayExpression(
       node.decorators.map(decorator => decorator.expression),
@@ -47,7 +52,12 @@ function getKey(node) {
 
 // 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, */ classRef, superRef, path) {
+function extractElementDescriptor(
+  this: File,
+  classRef: t.Identifier,
+  superRef: t.Identifier,
+  path: ClassElementPath,
+) {
   const { node, scope } = path;
   const isMethod = path.isClassMethod();
 
@@ -68,17 +78,17 @@ function extractElementDescriptor(/* this: File, */ classRef, superRef, path) {
   }).replace();
 
   const properties: t.ObjectExpression["properties"] = [
-    prop("kind", t.stringLiteral(isMethod ? node.kind : "field")),
-    prop("decorators", takeDecorators(node)),
+    prop("kind", t.stringLiteral(t.isClassMethod(node) ? node.kind : "field")),
+    prop("decorators", takeDecorators(node as Decorable)),
     prop("static", node.static && t.booleanLiteral(true)),
     prop("key", getKey(node)),
   ].filter(Boolean);
 
-  if (isMethod) {
+  if (t.isClassMethod(node)) {
     const id = node.computed ? null : node.key;
     t.toExpression(node);
     properties.push(prop("value", nameFunction({ node, id, scope }) || node));
-  } else if (node.value) {
+  } else if (t.isClassProperty(node) && node.value) {
     properties.push(
       method("value", template.statements.ast`return ${node.value}`),
     );
@@ -91,7 +101,7 @@ function extractElementDescriptor(/* this: File, */ classRef, superRef, path) {
   return t.objectExpression(properties);
 }
 
-function addDecorateHelper(file) {
+function addDecorateHelper(file: File) {
   try {
     return file.addHelper("decorate");
   } catch (err) {
@@ -105,7 +115,15 @@ function addDecorateHelper(file) {
   }
 }
 
-export function buildDecoratedClass(ref, path, elements, file) {
+type ClassElement = t.Class["body"]["body"][number];
+type ClassElementPath = NodePath<ClassElement>;
+
+export function buildDecoratedClass(
+  ref: t.Identifier,
+  path: NodePath<t.Class>,
+  elements: ClassElementPath[],
+  file: File,
+) {
   const { node, scope } = path;
   const initializeId = scope.generateUidIdentifier("initialize");
   const isDeclaration = node.id && path.isDeclaration();
@@ -115,7 +133,7 @@ export function buildDecoratedClass(ref, path, elements, file) {
   node.type = "ClassDeclaration";
   if (!node.id) node.id = t.cloneNode(ref);
 
-  let superId;
+  let superId: t.Identifier;
   if (superClass) {
     superId = scope.generateUidIdentifierBasedOnNode(node.superClass, "super");
     node.superClass = superId;
@@ -124,7 +142,7 @@ export function buildDecoratedClass(ref, path, elements, file) {
   const classDecorators = takeDecorators(node);
   const definitions = t.arrayExpression(
     elements
-      // Ignore TypeScript's abstract methods (see #10514)
+      // @ts-expect-error Ignore TypeScript's abstract methods (see #10514)
       .filter(element => !element.node.abstract)
       .map(extractElementDescriptor.bind(file, node.id, superId)),
   );
@@ -155,9 +173,9 @@ export function buildDecoratedClass(ref, path, elements, file) {
 
   return {
     instanceNodes: [template.statement.ast`${t.cloneNode(initializeId)}(this)`],
-    wrapClass(path) {
+    wrapClass(path: NodePath<t.Class>) {
       path.replaceWith(replacement);
-      return path.get(classPathDesc);
+      return path.get(classPathDesc) as NodePath;
     },
   };
 }
diff --git a/packages/babel-helper-create-class-features-plugin/src/features.ts b/packages/babel-helper-create-class-features-plugin/src/features.ts
@@ -1,3 +1,5 @@
+import type { File } from "@babel/core";
+import type { NodePath } from "@babel/traverse";
 import { hasOwnDecorators } from "./decorators";
 
 export const FEATURES = Object.freeze({
@@ -36,7 +38,7 @@ const looseKey = "@babel/plugin-class-features/looseKey";
 const looseLowPriorityKey =
   "@babel/plugin-class-features/looseLowPriorityKey/#__internal__@babel/preset-env__please-overwrite-loose-instead-of-throwing";
 
-export function enableFeature(file, feature, loose) {
+export function enableFeature(file: File, feature: number, loose: boolean) {
   // We can't blindly enable the feature because, if it was already set,
   // "loose" can't be changed, so that
   //   @babel/plugin-class-properties { loose: true }
@@ -46,12 +48,14 @@ export function enableFeature(file, feature, loose) {
   if (!hasFeature(file, feature) || canIgnoreLoose(file, feature)) {
     file.set(featuresKey, file.get(featuresKey) | feature);
     if (
+      // @ts-expect-error
       loose ===
       "#__internal__@babel/preset-env__prefer-true-but-false-is-ok-if-it-prevents-an-error"
     ) {
       setLoose(file, feature, true);
       file.set(looseLowPriorityKey, file.get(looseLowPriorityKey) | feature);
     } else if (
+      // @ts-expect-error
       loose ===
       "#__internal__@babel/preset-env__prefer-false-but-true-is-ok-if-it-prevents-an-error"
     ) {
@@ -62,8 +66,8 @@ export function enableFeature(file, feature, loose) {
     }
   }
 
-  let resolvedLoose: void | true | false;
-  let higherPriorityPluginName: void | string;
+  let resolvedLoose: boolean | undefined;
+  let higherPriorityPluginName: string | undefined;
 
   for (const [mask, name] of featuresSameLoose) {
     if (!hasFeature(file, mask)) continue;
@@ -103,26 +107,26 @@ export function enableFeature(file, feature, loose) {
   }
 }
 
-function hasFeature(file, feature) {
+function hasFeature(file: File, feature: number) {
   return !!(file.get(featuresKey) & feature);
 }
 
-export function isLoose(file, feature) {
+export function isLoose(file: File, feature: number) {
   return !!(file.get(looseKey) & feature);
 }
 
-function setLoose(file, feature, loose) {
+function setLoose(file: File, feature: number, loose: boolean) {
   if (loose) file.set(looseKey, file.get(looseKey) | feature);
   else file.set(looseKey, file.get(looseKey) & ~feature);
 
   file.set(looseLowPriorityKey, file.get(looseLowPriorityKey) & ~feature);
 }
 
-function canIgnoreLoose(file, feature) {
+function canIgnoreLoose(file: File, feature: number) {
   return !!(file.get(looseLowPriorityKey) & feature);
 }
 
-export function verifyUsedFeatures(path, file) {
+export function verifyUsedFeatures(path: NodePath, file: File) {
   if (hasOwnDecorators(path.node)) {
     if (!hasFeature(file, FEATURES.decorators)) {
       throw path.buildCodeFrameError(
@@ -145,8 +149,8 @@ export function verifyUsedFeatures(path, file) {
     }
   }
 
-  // NOTE: path.isPrivateMethod() it isn't supported in <7.2.0
-  if (path.isPrivateMethod?.()) {
+  // NOTE: path.isClassPrivateMethod() it isn't supported in <7.2.0
+  if (path.isClassPrivateMethod?.()) {
     if (!hasFeature(file, FEATURES.privateMethods)) {
       throw path.buildCodeFrameError("Class private methods are not enabled.");
     }