Fix comments print in IfStatement (#15076)

changelog_unreleased/javascript/15076.md

@@ -0,0 +1,18 @@
+#### Fix comments print in `IfStatement` (#15076 by @fisker)
+
+<!-- prettier-ignore -->
+```js
+function a(b) {
+  if (b) return 1; // comment
+  else return 2;
+}
+
+/* Prettier stable */
+Error: Comment "comment" was not printed. Please report this error!
+
+/* Prettier main */
+function a(b) {
+  if (b) return 1; // comment
+  else return 2;
+}
+```

src/language-js/comments/handle-comments.js

@@ -208,7 +208,9 @@ function handleIfStatementComments({
         addDanglingComment(
           precedingNode,
           comment,
-          markerForIfWithoutBlockAndSameLineComment,
+          precedingNode.type === "ExpressionStatement"
+            ? markerForIfWithoutBlockAndSameLineComment
+            : undefined,
         );
       } else {
         addDanglingComment(enclosingNode, comment);

tests/format/js/if/__snapshots__/jsfmt.spec.js.snap

@@ -93,26 +93,44 @@ parsers: ["babel", "flow", "typescript"]
 printWidth: 80
                                                                                 | printWidth
 =====================================input======================================
-if (a === 0) doSomething(); // comment A1
+     if (a === 0) doSomething(); // comment A1
 else if (a === 1) doSomethingElse(); // comment B1
 else if (a === 2) doSomethingElse(); // comment C1
 
-if (a === 0) doSomething(); /* comment A2 */
+     if (a === 0) doSomething(); /* comment A2 */
 else if (a === 1) doSomethingElse(); /* comment B2 */
 else if (a === 2) doSomethingElse(); /* comment C2 */
 
-if (a === 0) expr; // comment A3
+     if (a === 0) expr; // comment A3
 else if (a === 1) expr; // comment B3
 else if (a === 2) expr; // comment C3
 
-if (a === 0) expr; /* comment A4 */
+     if (a === 0) expr; /* comment A4 */
 else if (a === 1) expr; /* comment B4 */
 else if (a === 2) expr; /* comment C4 */
 
-if (a === 0) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment A5
+     if (a === 0) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment A5
 else if (a === 1) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment B5
 else if (a === 2) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment C5
 
+function a() {
+  if (a) return; /* comment 6a */
+  else return 2;
+
+  if (a) return 1; /* comment 6b */
+  else return 2;
+
+  if (a) throw e; /* comment 6d */
+  else return 2;
+
+  // TODO[@fisker]: fix this
+  // if (a) var a = 1; /* comment 6e */
+  // else return 2;
+
+  if (a) if (b); /* comment 6f */
+  else return 2;
+}
+
 =====================================output=====================================
 if (a === 0) doSomething(); // comment A1
 else if (a === 1) doSomethingElse(); // comment B1
@@ -137,6 +155,25 @@ else if (a === 1)
 else if (a === 2)
   looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment C5
 
+function a() {
+  if (a) return /* comment 6a */;
+  else return 2;
+
+  if (a) return 1 /* comment 6b */;
+  else return 2;
+
+  if (a) throw e /* comment 6d */;
+  else return 2;
+
+  // TODO[@fisker]: fix this
+  // if (a) var a = 1; /* comment 6e */
+  // else return 2;
+
+  if (a)
+    if (b /* comment 6f */);
+    else return 2;
+}
+
 ================================================================================
 `;
 

tests/format/js/if/expr_and_same_line_comments.js

@@ -1,19 +1,37 @@
-if (a === 0) doSomething(); // comment A1
+     if (a === 0) doSomething(); // comment A1
 else if (a === 1) doSomethingElse(); // comment B1
 else if (a === 2) doSomethingElse(); // comment C1
 
-if (a === 0) doSomething(); /* comment A2 */
+     if (a === 0) doSomething(); /* comment A2 */
 else if (a === 1) doSomethingElse(); /* comment B2 */
 else if (a === 2) doSomethingElse(); /* comment C2 */
 
-if (a === 0) expr; // comment A3
+     if (a === 0) expr; // comment A3
 else if (a === 1) expr; // comment B3
 else if (a === 2) expr; // comment C3
 
-if (a === 0) expr; /* comment A4 */
+     if (a === 0) expr; /* comment A4 */
 else if (a === 1) expr; /* comment B4 */
 else if (a === 2) expr; /* comment C4 */
 
-if (a === 0) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment A5
+     if (a === 0) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment A5
 else if (a === 1) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment B5
 else if (a === 2) looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong; // comment C5
+
+function a() {
+  if (a) return; /* comment 6a */
+  else return 2;
+
+  if (a) return 1; /* comment 6b */
+  else return 2;
+
+  if (a) throw e; /* comment 6d */
+  else return 2;
+
+  // TODO[@fisker]: fix this
+  // if (a) var a = 1; /* comment 6e */
+  // else return 2;
+
+  if (a) if (b); /* comment 6f */
+  else return 2;
+}