Fix union type should be printed in the multi-line variant when there are comments (#13860)

Co-authored-by: fisker Cheung <lionkay@gmail.com>

changelog_unreleased/typescript/13860.md

@@ -0,0 +1,18 @@
+#### Fix union type should be printed in the multi-line variant when there are comments (#13860 by @PerfectPan)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+type FooBar = 
+  | Number // this documents the first option
+  | void // this documents the second option
+  ;
+
+// Prettier stable
+type FooBar = Number | void; // this documents the first option // this documents the second option
+
+// Prettier main
+type FooBar =
+  | Number // this documents the first option
+  | void; // this documents the second option
+```

src/language-js/print/type-annotation.js

@@ -16,6 +16,7 @@ import {
   hasLeadingOwnLineComment,
   isObjectTypePropertyAFunction,
   shouldPrintComma,
+  hasComment,
 } from "../utils/index.js";
 import { printAssignment } from "./assignment.js";
 import {
@@ -47,7 +48,9 @@ function shouldHugType(node) {
         node.type === "TSTypeReference"
     );
 
-    if (node.types.length - 1 === voidCount && hasObject) {
+    const hasComments = node.types.some((node) => hasComment(node));
+
+    if (node.types.length - 1 === voidCount && hasObject && !hasComments) {
       return true;
     }
   }

tests/format/typescript/union/__snapshots__/jsfmt.spec.js.snap

@@ -47,6 +47,35 @@ interface RelayProps {
   } | null> | null | void,
 }
 
+interface RelayProps {
+  articles: Array<{
+    __id: string,
+  } | null>
+  | null // articles type may be null
+  | void, // articles type may be void
+}
+
+type FooBar = null // null
+| { /** x **/
+  y: number;
+  z: string;
+} // this documents the first option
+  | void // this documents the second option
+  ;
+
+type FooBarWithoutComment = null
+  | {
+  y: number;
+  z: string;
+}
+  | void
+  ;
+
+type FooBar2 =
+  | Number // this documents the first option
+  | void // this documents the second option
+  ;
+
 type UploadState<E, EM, D>
   // The upload hasnt begun yet
   = {type: "Not_begun"}
@@ -90,6 +119,32 @@ interface RelayProps {
   } | null> | null | void;
 }
 
+interface RelayProps {
+  articles:
+    | Array<{
+        __id: string;
+      } | null>
+    | null // articles type may be null
+    | void; // articles type may be void
+}
+
+type FooBar =
+  | null // null
+  | {
+      /** x **/ y: number;
+      z: string;
+    } // this documents the first option
+  | void; // this documents the second option
+
+type FooBarWithoutComment = null | {
+  y: number;
+  z: string;
+} | void;
+
+type FooBar2 =
+  | Number // this documents the first option
+  | void; // this documents the second option
+
 type UploadState<E, EM, D> =
   // The upload hasnt begun yet
   | { type: "Not_begun" }

tests/format/typescript/union/inlining.ts

@@ -7,6 +7,35 @@ interface RelayProps {
   } | null> | null | void,
 }
 
+interface RelayProps {
+  articles: Array<{
+    __id: string,
+  } | null>
+  | null // articles type may be null
+  | void, // articles type may be void
+}
+
+type FooBar = null // null
+| { /** x **/
+  y: number;
+  z: string;
+} // this documents the first option
+  | void // this documents the second option
+  ;
+
+type FooBarWithoutComment = null
+  | {
+  y: number;
+  z: string;
+}
+  | void
+  ;
+
+type FooBar2 =
+  | Number // this documents the first option
+  | void // this documents the second option
+  ;
+
 type UploadState<E, EM, D>
   // The upload hasnt begun yet
   = {type: "Not_begun"}