fix TS errors

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

@@ -38,7 +38,7 @@ interface Options {
   name: string;
   feature: number;
   loose?: boolean;
-  inherits?: () => Options;
+  inherits?: (api: any, options: any) => any;
   // same as PluginObject.manipulateOptions
   manipulateOptions: (options: unknown, parserOpts: ParserOptions) => void;
   // TODO(flow->ts): change to babel api
@@ -52,6 +52,7 @@ export function createClassFeaturePlugin({
   manipulateOptions,
   // TODO(Babel 8): Remove the default value
   api = { assumption: () => void 0 },
+  inherits,
 }: Options) {
   const setPublicClassFields = api.assumption("setPublicClassFields");
   const privateFieldsAsProperties = api.assumption("privateFieldsAsProperties");
@@ -86,6 +87,7 @@ export function createClassFeaturePlugin({
   return {
     name,
     manipulateOptions,
+    inherits,
 
     pre() {
       enableFeature(this.file, feature, loose);

packages/babel-plugin-proposal-decorators/src/index.ts

@@ -26,18 +26,17 @@ export default declare((api, options) => {
   } else if (version === "2021-12") {
     return transformer2021_12(api, options);
   } else {
-    const plugin = createClassFeaturePlugin({
+    return createClassFeaturePlugin({
       name: "proposal-decorators",
 
       api,
       feature: FEATURES.decorators,
+      inherits: syntaxDecorators,
       // loose: options.loose, Not supported
 
       manipulateOptions({ generatorOpts }) {
         generatorOpts.decoratorsBeforeExport = decoratorsBeforeExport;
       },
     });
-    plugin.inherits = syntaxDecorators;
-    return plugin;
   }
 });