Merge pull request #7811 from Microsoft/transforms-fixClassExpressionIndentation

Fixes indentation of class expression bodies

src/compiler/printer.ts

@@ -1396,6 +1396,11 @@ const _super = (function (geti, seti) {
                 const body = node.body;
                 if (body) {
                     if (isBlock(body)) {
+                        const indentedFlag = getNodeEmitFlags(node) & NodeEmitFlags.Indented;
+                        if (indentedFlag) {
+                            increaseIndent();
+                        }
+
                         const savedTempFlags = tempFlags;
                         tempFlags = 0;
                         startLexicalEnvironment();
@@ -1403,6 +1408,11 @@ const _super = (function (geti, seti) {
                         write(" {");
                         emitBlockFunctionBody(node, body);
                         write("}");
+
+                        if (indentedFlag) {
+                            decreaseIndent();
+                        }
+
                         tempFlags = savedTempFlags;
                     }
                     else {
@@ -1497,6 +1507,12 @@ const _super = (function (geti, seti) {
                 emitModifiers(node, node.modifiers);
                 write("class");
                 emitWithPrefix(" ", node.name);
+
+                const indentedFlag = getNodeEmitFlags(node) & NodeEmitFlags.Indented;
+                if (indentedFlag) {
+                    increaseIndent();
+                }
+
                 emitTypeParameters(node, node.typeParameters);
                 emitList(node, node.heritageClauses, ListFormat.ClassHeritageClauses);
 
@@ -1507,6 +1523,10 @@ const _super = (function (geti, seti) {
                 emitList(node, node.members, ListFormat.ClassMembers);
                 write("}");
 
+                if (indentedFlag) {
+                    decreaseIndent();
+                }
+
                 tempFlags = savedTempFlags;
             }
 

src/compiler/transformers/es6.ts

@@ -607,14 +607,23 @@ namespace ts {
             //      }(D))
 
             const baseTypeNode = getClassExtendsHeritageClauseElement(node);
+            const classFunction = createFunctionExpression(
+                /*asteriskToken*/ undefined,
+                /*name*/ undefined,
+                baseTypeNode ? [createParameter("_super")] : [],
+                transformClassBody(node, baseTypeNode !== undefined)
+            );
+
+            // To preserve the behavior of the old emitter, we explicitly indent
+            // the body of the function here if it was requested in an earlier
+            // transformation.
+            if (getNodeEmitFlags(node) & NodeEmitFlags.Indented) {
+                setNodeEmitFlags(classFunction, NodeEmitFlags.Indented);
+            }
+
             return createParen(
                 createCall(
-                    createFunctionExpression(
-                        /*asteriskToken*/ undefined,
-                        /*name*/ undefined,
-                        baseTypeNode ? [createParameter("_super")] : [],
-                        transformClassBody(node, baseTypeNode !== undefined)
-                    ),
+                    classFunction,
                     baseTypeNode
                         ? [visitNode(baseTypeNode.expression, visitor, isExpression)]
                         : []

src/compiler/transformers/ts.ts

@@ -673,6 +673,10 @@ namespace ts {
                 const expressions: Expression[] = [];
                 const temp = createTempVariable();
                 hoistVariableDeclaration(temp);
+
+                // To preserve the behavior of the old emitter, we explicitly indent
+                // the body of a class with static initializers.
+                setNodeEmitFlags(classExpression, NodeEmitFlags.Indented | getNodeEmitFlags(classExpression));
                 addNode(expressions, createAssignment(temp, classExpression), true);
                 addNodes(expressions, generateInitializedPropertyExpressions(node, staticProperties, temp), true);
                 addNode(expressions, temp, true);

src/compiler/types.ts

@@ -2873,7 +2873,8 @@ namespace ts {
         CapturesThis = 1 << 9,                   // The function captures a lexical `this`
         NoSourceMap = 1 << 10,                   // Do not emit a source map location for this node.
         NoNestedSourceMaps = 1 << 11,            // Do not emit source map locations for children of this node.
-        PrefixExportedLocal = 1 << 12,
+        PrefixExportedLocal = 1 << 12,           // Ensure an export prefix is added for an identifier that points to an exported declaration with a local name (see SymbolFlags.ExportHasLocal).
+        Indented = 1 << 13,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
     }
 
     /** Additional context provided to `visitEachChild` */

tests/baselines/reference/classExpressionWithStaticProperties1.js

@@ -3,10 +3,10 @@ var v = class C { static a = 1; static b = 2 };
 
 //// [classExpressionWithStaticProperties1.js]
 var v = (_a = (function () {
-    function C() {
-    }
-    return C;
-}()),
+        function C() {
+        }
+        return C;
+    }()),
     _a.a = 1,
     _a.b = 2,
     _a);

tests/baselines/reference/classExpressionWithStaticProperties2.js

@@ -3,10 +3,10 @@ var v = class C { static a = 1; static b };
 
 //// [classExpressionWithStaticProperties2.js]
 var v = (_a = (function () {
-    function C() {
-    }
-    return C;
-}()),
+        function C() {
+        }
+        return C;
+    }()),
     _a.a = 1,
     _a);
 var _a;

tests/baselines/reference/classExpressionWithStaticPropertiesES61.js

@@ -3,7 +3,7 @@ var v = class C { static a = 1; static b = 2 };
 
 //// [classExpressionWithStaticPropertiesES61.js]
 var v = (_a = class C {
-},
+    },
     _a.a = 1,
     _a.b = 2,
     _a);

tests/baselines/reference/classExpressionWithStaticPropertiesES62.js

@@ -3,7 +3,7 @@ var v = class C { static a = 1; static b };
 
 //// [classExpressionWithStaticPropertiesES62.js]
 var v = (_a = class C {
-},
+    },
     _a.a = 1,
     _a);
 var _a;