Merge pull request #3945 from Microsoft/bulkReexportInSystem

System: use batching when doing star exports

Author: vladima

Diff for: src/compiler/emitter.ts

@@ -5779,17 +5779,21 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                     write(`function ${exportStarFunction}(m) {`);
                     increaseIndent();
                     writeLine();
+                    write(`var exports = {};`);
+                    writeLine();
                     write(`for(var n in m) {`);
                     increaseIndent();
                     writeLine();
                     write(`if (n !== "default"`);
                     if (localNames) {
                         write(`&& !${localNames}.hasOwnProperty(n)`);
                     }
-                    write(`) ${exportFunctionForFile}(n, m[n]);`);
+                    write(`) exports[n] = m[n];`);
                     decreaseIndent();
                     writeLine();
                     write("}");
+                    writeLine();
+                    write(`${exportFunctionForFile}(exports);`)
                     decreaseIndent();
                     writeLine();
                     write("}");
@@ -6122,16 +6126,23 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                             if ((<ExportDeclaration>importNode).exportClause) {
                                 // export {a, b as c} from 'foo'
                                 // emit as:
-                                // exports('a', _foo["a"])
-                                // exports('c', _foo["b"])
+                                // var reexports = {}
+                                // reexports['a'] = _foo["a"];
+                                // reexports['c'] = _foo["b"];
+                                // exports_(reexports);
+                                let reexportsVariableName = makeUniqueName("reexports");
+                                writeLine();
+                                write(`var ${reexportsVariableName} = {};`)
+                                writeLine();
                                 for (let e of (<ExportDeclaration>importNode).exportClause.elements) {
-                                    writeLine();
-                                    write(`${exportFunctionForFile}("`);
+                                    write(`${reexportsVariableName}["`);
                                     emitNodeWithoutSourceMap(e.name);
-                                    write(`", ${parameterName}["`);
+                                    write(`"] = ${parameterName}["`);
                                     emitNodeWithoutSourceMap(e.propertyName || e.name);
-                                    write(`"]);`);
+                                    write(`"];`);
+                                    writeLine();
                                 }
+                                write(`${exportFunctionForFile}(${reexportsVariableName});`);
                             }
                             else {
                                 writeLine();

Diff for: tests/baselines/reference/systemModule11.js

@@ -51,9 +51,11 @@ System.register(['bar'], function(exports_1) {
         'foo': true
     };
     function exportStar_1(m) {
+        var exports = {};
         for(var n in m) {
-            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports_1(n, m[n]);
+            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports[n] = m[n];
         }
+        exports_1(exports);
     }
     return {
         setters:[
@@ -72,9 +74,11 @@ System.register(['bar'], function(exports_1) {
         'y1': true
     };
     function exportStar_1(m) {
+        var exports = {};
         for(var n in m) {
-            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports_1(n, m[n]);
+            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports[n] = m[n];
         }
+        exports_1(exports);
     }
     return {
         setters:[
@@ -96,15 +100,19 @@ System.register(['a', 'bar'], function(exports_1) {
         'z': true
     };
     function exportStar_1(m) {
+        var exports = {};
         for(var n in m) {
-            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports_1(n, m[n]);
+            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports[n] = m[n];
         }
+        exports_1(exports);
     }
     return {
         setters:[
             function (_a_1) {
-                exports_1("x", _a_1["x"]);
-                exports_1("z", _a_1["y"]);
+                var reexports_1 = {};
+                reexports_1["x"] = _a_1["x"];
+                reexports_1["z"] = _a_1["y"];
+                exports_1(reexports_1);
             },
             function (_bar_1) {
                 exportStar_1(_bar_1);
@@ -123,8 +131,10 @@ System.register(['a'], function(exports_1) {
     return {
         setters:[
             function (_a_1) {
-                exports_1("s", _a_1["s"]);
-                exports_1("s2", _a_1["s1"]);
+                var reexports_1 = {};
+                reexports_1["s"] = _a_1["s"];
+                reexports_1["s2"] = _a_1["s1"];
+                exports_1(reexports_1);
             }],
         execute: function() {
             exports_1("z", z);
@@ -136,9 +146,11 @@ System.register(['a'], function(exports_1) {
 System.register(['a'], function(exports_1) {
     function foo() { }
     function exportStar_1(m) {
+        var exports = {};
         for(var n in m) {
-            if (n !== "default") exports_1(n, m[n]);
+            if (n !== "default") exports[n] = m[n];
         }
+        exports_1(exports);
     }
     return {
         setters:[

Diff for: tests/baselines/reference/systemModule9.js

@@ -30,9 +30,11 @@ System.register(['file1', 'file2', 'file3', 'file4', 'file5', 'file6', 'file7'],
         'z': true
     };
     function exportStar_1(m) {
+        var exports = {};
         for(var n in m) {
-            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports_1(n, m[n]);
+            if (n !== "default"&& !exportedNames_1.hasOwnProperty(n)) exports[n] = m[n];
         }
+        exports_1(exports);
     }
     return {
         setters:[