Fix comment style when placed after if statement test (#2675)

* Fix comment style when placed after the test of an if statement

* Add tests

* Do a bit of refactoring

* Fix lint errors

* Handle skipping comments

* Account for multiple-line comments

* Add more tests

* Change function name

* Add more tests

* Refactor

* Add some comments

* Do away with getPreviousNonSpaceNonCommentCharacter

* Improve comment and code on handling if statement comments

* Refactor

* Fix a bug

src/comments.js

@@ -466,12 +466,12 @@ function handleIfStatementComments(
   }
 
   // We unfortunately have no way using the AST or location of nodes to know
-  // if the comment is positioned before or after the condition parenthesis:
+  // if the comment is positioned before the condition parenthesis:
   //   if (a /* comment */) {}
-  //   if (a) /* comment */ {}
   // The only workaround I found is to look at the next character to see if
   // it is a ).
-  if (getNextNonSpaceNonCommentCharacter(text, comment) === ")") {
+  const nextCharacter = getNextNonSpaceNonCommentCharacter(text, comment);
+  if (nextCharacter === ")") {
     addTrailingComment(precedingNode, comment);
     return true;
   }
@@ -486,6 +486,16 @@ function handleIfStatementComments(
     return true;
   }
 
+  // For comments positioned after the condition parenthesis in an if statement
+  // before the consequent with or without brackets on, such as
+  // if (a) /* comment */ {} or if (a) /* comment */ true,
+  // we look at the next character to see if it is a { or if the following node
+  // is the consequent for the if statement
+  if (nextCharacter === "{" || enclosingNode.consequent === followingNode) {
+    addLeadingComment(followingNode, comment);
+    return true;
+  }
+
   return false;
 }
 

tests/comments/__snapshots__/jsfmt.spec.js.snap

@@ -328,10 +328,45 @@ else if (4) {
 else {
 }
 
-if (1)
-{}
+if (5) // comment
+true
+
+if (6) // comment
+{true}
+else if (7) // comment
+true
 else // comment
-{}
+{true}
+
+if (8) // comment
+// comment
+{true}
+else if (9) // comment
+// comment
+true
+else // comment
+// comment
+{true}
+
+if (10) /* comment */ // comment
+{true}
+else if (11) /* comment */
+true
+else if (12) // comment /* comment */ // comment
+true
+else if (13) /* comment */ /* comment */ // comment
+true
+else /* comment */
+{true}
+
+if (14) // comment
+/* comment */
+// comment
+{true}
+else if (15) // comment
+/* comment */
+/* comment */ // comment
+true
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 if (1) {
   // comment
@@ -352,11 +387,63 @@ else if (4) {
   // comment
 }
 
-if (1) {
-} else {
+if (5)
   // comment
+  true;
+
+if (6) {
+  // comment
+  true;
+} else if (7)
+  // comment
+  true;
+else {
+  // comment
+  true;
 }
 
+if (8) {
+  // comment
+  // comment
+  true;
+} else if (9)
+  // comment
+  // comment
+  true;
+else {
+  // comment
+  // comment
+  true;
+}
+
+if (10) {
+  /* comment */ // comment
+  true;
+} else if (11)
+  /* comment */
+  true;
+else if (12)
+  // comment /* comment */ // comment
+  true;
+else if (13)
+  /* comment */ /* comment */ // comment
+  true;
+else {
+  /* comment */
+  true;
+}
+
+if (14) {
+  // comment
+  /* comment */
+  // comment
+  true;
+} else if (15)
+  // comment
+  /* comment */
+  /* comment */ // comment
+  true;
+
 `;
 
 exports[`issues.js 1`] = `

tests/comments/if.js

@@ -20,7 +20,42 @@ else if (4) {
 else {
 }
 
-if (1)
-{}
+if (5) // comment
+true
+
+if (6) // comment
+{true}
+else if (7) // comment
+true
 else // comment
-{}
+{true}
+
+if (8) // comment
+// comment
+{true}
+else if (9) // comment
+// comment
+true
+else // comment
+// comment
+{true}
+
+if (10) /* comment */ // comment
+{true}
+else if (11) /* comment */
+true
+else if (12) // comment /* comment */ // comment
+true
+else if (13) /* comment */ /* comment */ // comment
+true
+else /* comment */
+{true}
+
+if (14) // comment
+/* comment */
+// comment
+{true}
+else if (15) // comment
+/* comment */
+/* comment */ // comment
+true

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

@@ -54,6 +54,24 @@ async function f() {
   }
 }
 
+async function f() {
+  if (untrackedChoice === 0) /* Cancel */
+    null;
+  else if (untrackedChoice === 1) /* Add */
+    shouldAmend = true;
+  else if (untrackedChoice === 2) /* Allow Untracked */
+    allowUntracked = true;
+}
+
+async function f() {
+  if (untrackedChoice === 0) /* Cancel */ // Cancel
+    null;
+  else if (untrackedChoice === 1) /* Add */ // Add
+    shouldAmend = true;
+  else if (untrackedChoice === 2) /* Allow Untracked */ // Allow Untracked
+    allowUntracked = true;
+}
+
 async function f() {
   if (untrackedChoice === 0)
     /* Cancel */ {
@@ -92,6 +110,30 @@ async function f() {
   }
 }
 
+async function f() {
+  if (untrackedChoice === 0)
+    /* Cancel */
+    null;
+  else if (untrackedChoice === 1)
+    /* Add */
+    shouldAmend = true;
+  else if (untrackedChoice === 2)
+    /* Allow Untracked */
+    allowUntracked = true;
+}
+
+async function f() {
+  if (untrackedChoice === 0)
+    /* Cancel */ // Cancel
+    null;
+  else if (untrackedChoice === 1)
+    /* Add */ // Add
+    shouldAmend = true;
+  else if (untrackedChoice === 2)
+    /* Allow Untracked */ // Allow Untracked
+    allowUntracked = true;
+}
+
 async function f() {
   if (untrackedChoice === 0) {
     /* Cancel */ return null;

tests/if/if_comments.js

@@ -9,6 +9,24 @@ async function f() {
   }
 }
 
+async function f() {
+  if (untrackedChoice === 0) /* Cancel */
+    null;
+  else if (untrackedChoice === 1) /* Add */
+    shouldAmend = true;
+  else if (untrackedChoice === 2) /* Allow Untracked */
+    allowUntracked = true;
+}
+
+async function f() {
+  if (untrackedChoice === 0) /* Cancel */ // Cancel
+    null;
+  else if (untrackedChoice === 1) /* Add */ // Add
+    shouldAmend = true;
+  else if (untrackedChoice === 2) /* Allow Untracked */ // Allow Untracked
+    allowUntracked = true;
+}
+
 async function f() {
   if (untrackedChoice === 0)
     /* Cancel */ {