Preserve newlines between try/catch/finally, if/else, do/while (microsoft#39280)

* Preserve newlines between try/catch, if/else, do/while

* Update baselines

Author: andrewbranch

src/compiler/emitter.ts

@@ -2667,7 +2667,7 @@ namespace ts {
             emitTokenWithComment(SyntaxKind.CloseParenToken, node.expression.end, writePunctuation, node);
             emitEmbeddedStatement(node, node.thenStatement);
             if (node.elseStatement) {
-                writeLineOrSpace(node);
+                writeLineOrSpace(node, node.thenStatement, node.elseStatement);
                 emitTokenWithComment(SyntaxKind.ElseKeyword, node.thenStatement.end, writeKeyword, node);
                 if (node.elseStatement.kind === SyntaxKind.IfStatement) {
                     writeSpace();
@@ -2690,11 +2690,11 @@ namespace ts {
         function emitDoStatement(node: DoStatement) {
             emitTokenWithComment(SyntaxKind.DoKeyword, node.pos, writeKeyword, node);
             emitEmbeddedStatement(node, node.statement);
-            if (isBlock(node.statement)) {
+            if (isBlock(node.statement) && !preserveSourceNewlines) {
                 writeSpace();
             }
             else {
-                writeLineOrSpace(node);
+                writeLineOrSpace(node, node.statement, node.expression);
             }
 
             emitWhileClause(node, node.statement.end);
@@ -2836,11 +2836,11 @@ namespace ts {
             writeSpace();
             emit(node.tryBlock);
             if (node.catchClause) {
-                writeLineOrSpace(node);
+                writeLineOrSpace(node, node.tryBlock, node.catchClause);
                 emit(node.catchClause);
             }
             if (node.finallyBlock) {
-                writeLineOrSpace(node);
+                writeLineOrSpace(node, node.catchClause || node.tryBlock, node.finallyBlock);
                 emitTokenWithComment(SyntaxKind.FinallyKeyword, (node.catchClause || node.tryBlock).end, writeKeyword, node);
                 writeSpace();
                 emit(node.finallyBlock);
@@ -4249,10 +4249,19 @@ namespace ts {
             return pos! < 0 ? pos! : pos! + tokenString.length;
         }
 
-        function writeLineOrSpace(node: Node) {
-            if (getEmitFlags(node) & EmitFlags.SingleLine) {
+        function writeLineOrSpace(parentNode: Node, prevChildNode: Node, nextChildNode: Node) {
+            if (getEmitFlags(parentNode) & EmitFlags.SingleLine) {
                 writeSpace();
             }
+            else if (preserveSourceNewlines) {
+                const lines = getLinesBetweenNodes(parentNode, prevChildNode, nextChildNode);
+                if (lines) {
+                    writeLine(lines);
+                }
+                else {
+                    writeSpace();
+                }
+            }
             else {
                 writeLine();
             }

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_Catch.ts

@@ -9,8 +9,7 @@ async function f():Promise<void> {
     try {
         const result = await fetch('https://typescriptlang.org');
         console.log(result);
-    }
-    catch (err) {
+    } catch (err) {
         console.log(err);
     }
 }

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchAndRej.ts

@@ -10,12 +10,10 @@ async function f():Promise<void> {
         try {
             const result = await fetch('https://typescriptlang.org');
             console.log(result);
-        }
-        catch (rejection) {
+        } catch (rejection) {
             console.log("rejected:", rejection);
         }
-    }
-    catch (err) {
+    } catch (err) {
         console.log(err);
     }
 }

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchAndRejRef.ts

@@ -19,12 +19,10 @@ async function f():Promise<void> {
         try {
             const result = await fetch('https://typescriptlang.org');
             return res(result);
-        }
-        catch (rejection) {
+        } catch (rejection) {
             return rej(rejection);
         }
-    }
-    catch (err) {
+    } catch (err) {
         return catch_err(err);
     }
 }

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchFollowedByThen.js

@@ -19,8 +19,7 @@ async function f(){
     try {
         const result_1 = await fetch("https://typescriptlang.org");
         result = await res(result_1);
-    }
-    catch (reject) {
+    } catch (reject) {
         result = await rej(reject);
     }
     return res(result);

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchFollowedByThen.ts

@@ -19,8 +19,7 @@ async function f(){
     try {
         const result_1 = await fetch("https://typescriptlang.org");
         result = await res(result_1);
-    }
-    catch (reject) {
+    } catch (reject) {
         result = await rej(reject);
     }
     return res(result);

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchFollowedByThenMatchingTypes01.ts

@@ -19,8 +19,7 @@ async function f(){
     try {
         const result_1 = await fetch("https://typescriptlang.org");
         result = await res(result_1);
-    }
-    catch (reject) {
+    } catch (reject) {
         result = await rej(reject);
     }
     return res(result);

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchFollowedByThenMatchingTypes01NoAnnotations.js

@@ -19,8 +19,7 @@ async function f(){
     try {
         const result_1 = await fetch("https://typescriptlang.org");
         result = await res(result_1);
-    }
-    catch (reject) {
+    } catch (reject) {
         result = await rej(reject);
     }
     return res(result);

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchFollowedByThenMatchingTypes01NoAnnotations.ts

@@ -19,8 +19,7 @@ async function f(){
     try {
         const result_1 = await fetch("https://typescriptlang.org");
         result = await res(result_1);
-    }
-    catch (reject) {
+    } catch (reject) {
         result = await rej(reject);
     }
     return res(result);

tests/baselines/reference/convertToAsyncFunction/convertToAsyncFunction_CatchFollowedByThenMatchingTypes02.ts

@@ -15,8 +15,7 @@ async function f(){
     try {
         const res = await fetch("https://typescriptlang.org");
         result = 0;
-    }
-    catch (rej) {
+    } catch (rej) {
         result = 1;
     }
     return res(result);