Better support try/catch comments (#607)

Uses the same technique as for if/then/else. Added a helper function to make it easier.

Fixes #601

src/comments.js

@@ -145,7 +145,8 @@ function attach(comments, ast, text) {
       // We also need to check if it's the first line of the file.
       if (
         handleMemberExpressionComment(enclosingNode, followingNode, comment) ||
-          handleIfStatementComments(enclosingNode, followingNode, comment)
+          handleIfStatementComments(enclosingNode, followingNode, comment) ||
+          handleTryStatementComments(enclosingNode, followingNode, comment)
       ) {
         // We're good
       } else if (followingNode) {
@@ -286,6 +287,14 @@ function addBlockStatementFirstComment(node, comment) {
   }
 }
 
+function addBlockOrNotComment(node, comment) {
+  if (node.type === "BlockStatement") {
+    addBlockStatementFirstComment(node, comment);
+  } else {
+    addLeadingComment(node, comment);
+  }
+}
+
 // There are often comments before the else clause of if statements like
 //
 //   if (1) { ... }
@@ -315,11 +324,33 @@ function handleIfStatementComments(enclosingNode, followingNode, comment) {
   }
 
   if (followingNode.type === "IfStatement") {
-    if (followingNode.consequent.type === "BlockStatement") {
-      addBlockStatementFirstComment(followingNode.consequent, comment);
-    } else {
-      addLeadingComment(followingNode.consequent, comment);
-    }
+    addBlockOrNotComment(followingNode.consequent, comment);
+    return true;
+  }
+
+  return false;
+}
+
+// Same as IfStatement but for TryStatement
+function handleTryStatementComments(enclosingNode, followingNode, comment) {
+  if (
+    !enclosingNode || enclosingNode.type !== "TryStatement" || !followingNode
+  ) {
+    return false;
+  }
+
+  if (followingNode.type === "BlockStatement") {
+    addBlockStatementFirstComment(followingNode, comment);
+    return true;
+  }
+
+  if (followingNode.type === "TryStatement") {
+    addBlockOrNotComment(followingNode.finalizer, comment);
+    return true;
+  }
+
+  if (followingNode.type === "CatchClause") {
+    addBlockOrNotComment(followingNode.body, comment);
     return true;
   }
 

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

@@ -747,3 +747,59 @@ exports[`test jsx.js 2`] = `
 </div>;
 "
 `;
+
+exports[`test try.js 1`] = `
+"// comment 1
+try {
+  // comment 2
+}
+// comment 3
+catch(e) {
+  // comment 4
+}
+// comment 5
+finally // comment 6
+{
+  // comment 7
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// comment 1
+try {
+  // comment 2
+} catch (e) {
+  // comment 3
+  // comment 4
+} finally { // comment 6
+  // comment 5
+  // comment 7
+}
+"
+`;
+
+exports[`test try.js 2`] = `
+"// comment 1
+try {
+  // comment 2
+}
+// comment 3
+catch(e) {
+  // comment 4
+}
+// comment 5
+finally // comment 6
+{
+  // comment 7
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// comment 1
+try {
+  // comment 2
+} catch (e) {
+  // comment 3
+  // comment 4
+} finally { // comment 6
+  // comment 5
+  // comment 7
+}
+"
+`;

tests/comments/try.js

@@ -0,0 +1,13 @@
+// comment 1
+try {
+  // comment 2
+}
+// comment 3
+catch(e) {
+  // comment 4
+}
+// comment 5
+finally // comment 6
+{
+  // comment 7
+}