Refine typing for parserOverride in babel plugins (#17322)

vikr01 · web-flow · commit 73623f146a44 · 2025-05-23T11:51:23.000+02:00
diff --git a/packages/babel-core/src/config/plugin.ts b/packages/babel-core/src/config/plugin.ts
@@ -9,7 +9,7 @@ export default class Plugin {
   pre?: PluginObject["pre"];
   visitor: PluginObject["visitor"];
 
-  parserOverride?: Function;
+  parserOverride?: PluginObject["parserOverride"];
   generatorOverride?: Function;
 
   options: object;
diff --git a/packages/babel-core/src/config/validation/plugins.ts b/packages/babel-core/src/config/validation/plugins.ts
@@ -11,7 +11,7 @@ import type {
   OptionPath,
   RootPath,
 } from "./option-assertions.ts";
-import type { ParserOptions } from "@babel/parser";
+import type { parse, ParserOptions } from "@babel/parser";
 import type { Visitor } from "@babel/traverse";
 import type { ValidatedOptions } from "./options.ts";
 import type { File, PluginAPI, PluginPass } from "../../index.ts";
@@ -93,7 +93,9 @@ export type PluginObject<S extends PluginPass = PluginPass> = {
     dirname: string,
   ) => PluginObject;
   visitor?: Visitor<S>;
-  parserOverride?: Function;
+  parserOverride?: (
+    ...args: [...Parameters<typeof parse>, typeof parse]
+  ) => ReturnType<typeof parse>;
   generatorOverride?: Function;
 };
 
diff --git a/packages/babel-core/src/parser/index.ts b/packages/babel-core/src/parser/index.ts
@@ -29,7 +29,7 @@ export default function* parser(
     } else if (results.length === 1) {
       // If we want to allow async parsers
       yield* [];
-      if (typeof results[0].then === "function") {
+      if (typeof (results[0] as any).then === "function") {
         throw new Error(
           `You appear to be using an async parser plugin, ` +
             `which your current version of Babel does not support. ` +
