Don't print extra semicolon after prettier-ignored index-signature (#17538)

* Don't print extra semicolon after `prettier-ignore`d index-signature

* Update snapshots

* Add changelog

changelog_unreleased/typescript/17538.md

@@ -0,0 +1,22 @@
+#### Don't print extra semicolon after `prettier-ignore`d index-signature (#17538 by @sosukesuzuki)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+type foo = {
+  // prettier-ignore
+  [key: string]: bar;
+};
+
+// Prettier stable
+type foo = {
+  // prettier-ignore
+  [key: string]: bar;;
+};
+
+// Prettier main
+type foo = {
+  // prettier-ignore
+  [key: string]: bar;
+};
+```

src/language-js/print/object.js

@@ -159,7 +159,8 @@ function printObject(path, options, print) {
         ((lastElem.type === "TSPropertySignature" ||
           lastElem.type === "TSCallSignatureDeclaration" ||
           lastElem.type === "TSMethodSignature" ||
-          lastElem.type === "TSConstructSignatureDeclaration") &&
+          lastElem.type === "TSConstructSignatureDeclaration" ||
+          lastElem.type === "TSIndexSignature") &&
           hasComment(lastElem, CommentCheckFlags.PrettierIgnore))))
   );
 

tests/format/typescript/prettier-ignore/__snapshots__/format.test.js.snap

@@ -18,6 +18,26 @@ export const foo = // prettier-ignore
 ================================================================================
 `;
 
+exports[`issue-16927.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+type Foo = {
+    // prettier-ignore
+    [key: string]: bar;
+};
+
+=====================================output=====================================
+type Foo = {
+  // prettier-ignore
+  [key: string]: bar;
+};
+
+================================================================================
+`;
+
 exports[`mapped-types.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript"]

tests/format/typescript/prettier-ignore/issue-16927.ts

@@ -0,0 +1,4 @@
+type Foo = {
+    // prettier-ignore
+    [key: string]: bar;
+};