TypeScript: Preserve a last separator for ignored object and interface types (#9318)

* Preserve ignored TypeScript signature

* Add Changelog

changelog_unreleased/typescript/pr-9318.md

@@ -0,0 +1,21 @@
+#### Preserve a last separator for ignored object and interface types (#9318 by @sosukesuzuki)
+
+```ts
+// Input
+let x: {
+  // prettier-ignore
+  y: z;
+};
+
+// Prettier stable
+let x: {
+  // prettier-ignore
+  y: z;;
+};
+
+// Prettier master
+let x: {
+  // prettier-ignore
+  y: z;
+};
+```

src/language-js/printer-estree.js

@@ -1184,7 +1184,13 @@ function printPathNoParens(path, options, print, args) {
 
       const canHaveTrailingSeparator = !(
         n.inexact ||
-        (lastElem && lastElem.type === "RestElement")
+        (lastElem && lastElem.type === "RestElement") ||
+        (lastElem &&
+          (lastElem.type === "TSPropertySignature" ||
+            lastElem.type === "TSCallSignatureDeclaration" ||
+            lastElem.type === "TSMethodSignature" ||
+            lastElem.type === "TSConstructSignatureDeclaration") &&
+          hasNodeIgnoreComment(lastElem))
       );
 
       let content;

tests/typescript/interface/__snapshots__/jsfmt.spec.js.snap

@@ -314,6 +314,84 @@ interface T<T> {
   new<T>(): T<T>;
 }
 
+interface I {
+  // prettier-ignore
+  x: y;
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+}
+
+interface I {
+  // prettier-ignore
+  x: y;
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  (): void;
+}
+
+interface I {
+  // prettier-ignore
+  (): void,
+}
+
+interface I {
+  // prettier-ignore
+  (): void
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void;
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void,
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void
+}
+
+interface I {
+  // prettier-ignore
+  new ();
+}
+
+interface I {
+  // prettier-ignore
+  new (),
+}
+
+interface I {
+  // prettier-ignore
+  new ()
+}
+
 =====================================output=====================================
 interface Interface {
   // prettier-ignore
@@ -344,6 +422,84 @@ interface T<T> {
   new <T>(): T<T>
 }
 
+interface I {
+  // prettier-ignore
+  x: y;
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+}
+
+interface I {
+  // prettier-ignore
+  x: y;
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  (): void;
+}
+
+interface I {
+  // prettier-ignore
+  (): void,
+}
+
+interface I {
+  // prettier-ignore
+  (): void
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void;
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void,
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void
+}
+
+interface I {
+  // prettier-ignore
+  new ();
+}
+
+interface I {
+  // prettier-ignore
+  new (),
+}
+
+interface I {
+  // prettier-ignore
+  new ()
+}
+
 ================================================================================
 `;
 
@@ -382,6 +538,84 @@ interface T<T> {
   new<T>(): T<T>;
 }
 
+interface I {
+  // prettier-ignore
+  x: y;
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+}
+
+interface I {
+  // prettier-ignore
+  x: y;
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  (): void;
+}
+
+interface I {
+  // prettier-ignore
+  (): void,
+}
+
+interface I {
+  // prettier-ignore
+  (): void
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void;
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void,
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void
+}
+
+interface I {
+  // prettier-ignore
+  new ();
+}
+
+interface I {
+  // prettier-ignore
+  new (),
+}
+
+interface I {
+  // prettier-ignore
+  new ()
+}
+
 =====================================output=====================================
 interface Interface {
   // prettier-ignore
@@ -412,6 +646,84 @@ interface T<T> {
   new <T>(): T<T>;
 }
 
+interface I {
+  // prettier-ignore
+  x: y;
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+}
+
+interface I {
+  // prettier-ignore
+  x: y;
+  y: x;
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+  y: x;
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+  y: x;
+}
+
+interface I {
+  // prettier-ignore
+  (): void;
+}
+
+interface I {
+  // prettier-ignore
+  (): void,
+}
+
+interface I {
+  // prettier-ignore
+  (): void
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void;
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void,
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void
+}
+
+interface I {
+  // prettier-ignore
+  new ();
+}
+
+interface I {
+  // prettier-ignore
+  new (),
+}
+
+interface I {
+  // prettier-ignore
+  new ()
+}
+
 ================================================================================
 `;
 

tests/typescript/interface/ignore.ts

@@ -26,3 +26,81 @@ interface T<T> {
   new<T>(): T<T>;
   new<T>(): T<T>;
 }
+
+interface I {
+  // prettier-ignore
+  x: y;
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+}
+
+interface I {
+  // prettier-ignore
+  x: y;
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y,
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  x: y
+  y: x
+}
+
+interface I {
+  // prettier-ignore
+  (): void;
+}
+
+interface I {
+  // prettier-ignore
+  (): void,
+}
+
+interface I {
+  // prettier-ignore
+  (): void
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void;
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void,
+}
+
+interface I {
+  // prettier-ignore
+  foo(): void
+}
+
+interface I {
+  // prettier-ignore
+  new ();
+}
+
+interface I {
+  // prettier-ignore
+  new (),
+}
+
+interface I {
+  // prettier-ignore
+  new ()
+}