From 893fd3b1203c2c2dc196aba55759dce6c3a53478 Mon Sep 17 00:00:00 2001
From: fisker Cheung <lionkay@gmail.com>
Date: Wed, 26 Aug 2026 03:29:23 +0800
Subject: [PATCH] Add `isTypeAnnotation` (#19921)

---
 src/language-js/comments/handle-comments.js           |  4 ++--
 src/language-js/print/function-parameters.js          |  5 ++---
 src/language-js/print/type-annotation.js              | 11 ++++++-----
 .../utilities/is-type-annotation-a-function.js        |  2 +-
 src/language-js/utilities/node-types.js               |  5 +++++
 5 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/src/language-js/comments/handle-comments.js b/src/language-js/comments/handle-comments.js
index 019ec7f91..640e55285 100644
--- a/src/language-js/comments/handle-comments.js
+++ b/src/language-js/comments/handle-comments.js
@@ -28,6 +28,7 @@ import {
   isIntersectionType,
   isMemberExpression,
   isTypeAlias,
+  isTypeAnnotation,
   isUnionType,
 } from "../utilities/node-types.js";
 import { stripComments } from "../utilities/strip-comments.js";
@@ -994,8 +995,7 @@ function handleCommentsInDestructuringPattern({
     (enclosingNode.type === "ObjectPattern" ||
       enclosingNode.type === "ArrayPattern") &&
     enclosingNode.typeAnnotation === followingNode &&
-    (followingNode.type === "TSTypeAnnotation" ||
-      followingNode.type === "TypeAnnotation")
+    isTypeAnnotation(followingNode)
   ) {
     if (
       getNextNonSpaceNonCommentCharacter(text, locEnd(comment)) ===
diff --git a/src/language-js/print/function-parameters.js b/src/language-js/print/function-parameters.js
index 4c92e632c..c9ba40182 100644
--- a/src/language-js/print/function-parameters.js
+++ b/src/language-js/print/function-parameters.js
@@ -23,6 +23,7 @@ import {
   isArrayExpression,
   isObjectExpression,
   isObjectType,
+  isTypeAnnotation,
 } from "../utilities/node-types.js";
 import { isTestCall } from "../utilities/test-libraries.js";
 import {
@@ -209,9 +210,7 @@ function shouldHugTheOnlyFunctionParameter(node) {
     (parameter.type === "ObjectPattern" ||
       parameter.type === "ArrayPattern" ||
       (parameter.type === "Identifier" &&
-        parameter.typeAnnotation &&
-        (parameter.typeAnnotation.type === "TypeAnnotation" ||
-          parameter.typeAnnotation.type === "TSTypeAnnotation") &&
+        isTypeAnnotation(parameter.typeAnnotation) &&
         isObjectType(parameter.typeAnnotation.typeAnnotation)) ||
       (parameter.type === "FunctionTypeParam" &&
         isObjectType(parameter.typeAnnotation) &&
diff --git a/src/language-js/print/type-annotation.js b/src/language-js/print/type-annotation.js
index 384e970b6..a6ac57573 100644
--- a/src/language-js/print/type-annotation.js
+++ b/src/language-js/print/type-annotation.js
@@ -1,6 +1,10 @@
 import { CommentCheckFlags, hasComment } from "../utilities/comments.js";
 import { isSimpleType } from "../utilities/is-simple-type.js";
-import { isObjectType, isUnionType } from "../utilities/node-types.js";
+import {
+  isObjectType,
+  isTypeAnnotation,
+  isUnionType,
+} from "../utilities/node-types.js";
 import { shouldHugUnionType } from "./union-type.js";
 
 /**
@@ -40,10 +44,7 @@ function printTypeAnnotationProperty(
 
   let shouldPrintLeadingSpace = false;
 
-  if (
-    typeAnnotation.type === "TSTypeAnnotation" ||
-    typeAnnotation.type === "TypeAnnotation"
-  ) {
+  if (isTypeAnnotation(typeAnnotation)) {
     const firstToken = path.call(getTypeAnnotationFirstToken, propertyName);
 
     if (
diff --git a/src/language-js/utilities/is-type-annotation-a-function.js b/src/language-js/utilities/is-type-annotation-a-function.js
index a56d3708c..e31870756 100644
--- a/src/language-js/utilities/is-type-annotation-a-function.js
+++ b/src/language-js/utilities/is-type-annotation-a-function.js
@@ -5,7 +5,7 @@ import { hasSameLocStart } from "../location/index.js";
 // var f: (a) => void;
 function isTypeAnnotationAFunction(node) {
   return (
-    (node.type === "TypeAnnotation" || node.type === "TSTypeAnnotation") &&
+    node.type === "TypeAnnotation" &&
     node.typeAnnotation.type === "FunctionTypeAnnotation" &&
     !node.static &&
     !hasSameLocStart(node, node.typeAnnotation)
diff --git a/src/language-js/utilities/node-types.js b/src/language-js/utilities/node-types.js
index ea8db0af5..f5c2040e6 100644
--- a/src/language-js/utilities/node-types.js
+++ b/src/language-js/utilities/node-types.js
@@ -142,4 +142,9 @@ export const isTypeParameterInstantiation = createTypeCheckFunction([
   "TypeParameterInstantiation",
 ]);
 
+export const isTypeAnnotation = createTypeCheckFunction([
+  "TSTypeAnnotation",
+  "TypeAnnotation",
+]);
+
 export * from "./literal.js";