Revert "JS templates"

sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
index 41c78cd73255abd7f36481bddab5b857adaebfd9..c5dd94aaae0da35570c35080e1f94d7b88a4d23b 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart
@@ -148,65 +148,74 @@ class CodeEmitterTask extends CompilerTask {
     String valueParamName = compiler.enableMinification ? "v" : "value";
     String reflectableField = namer.reflectableField;
 
-    return js.statement('''
-      function generateAccessor(fieldDescriptor, accessors, cls) {
-        var fieldInformation = fieldDescriptor.split("-");
-        var field = fieldInformation[0];
-        var len = field.length;
-        var code = field.charCodeAt(len - 1);
-        var reflectable;
-        if (fieldInformation.length > 1) reflectable = true;
-             else reflectable = false;
-        code = ((code >= $RANGE1_FIRST) && (code <= $RANGE1_LAST))
-              ? code - $RANGE1_ADJUST
-              : ((code >= $RANGE2_FIRST) && (code <= $RANGE2_LAST))
-                ? code - $RANGE2_ADJUST
-                : ((code >= $RANGE3_FIRST) && (code <= $RANGE3_LAST))
-                  ? code - $RANGE3_ADJUST
-                  : $NO_FIELD_CODE;
-
-        if (code) {  // needsAccessor
-          var getterCode = code & 3;
-          var setterCode = code >> 2;
-          var accessorName = field = field.substring(0, len - 1);
-
-          var divider = field.indexOf(":");
-          if (divider > 0) { // Colon never in first position.
-            accessorName = field.substring(0, divider);
-            field = field.substring(divider + 1);
-          }
-
-          if (getterCode) {  // needsGetter
-            var args = (getterCode & 2) ? "$receiverParamName" : "";
-            var receiver = (getterCode & 1) ? "this" : "$receiverParamName";
-            var body = "return " + receiver + "." + field;
-            var property =
-                cls + ".prototype.${namer.getterPrefix}" + accessorName + "=";
-            var fn = "function(" + args + "){" + body + "}";
-            if (reflectable)
-              accessors.push(property + "\$reflectable(" + fn + ");\\n");
-            else
-              accessors.push(property + fn + ";\\n");
-          }
-
-          if (setterCode) {  // needsSetter
-            var args = (setterCode & 2)
-                ? "$receiverParamName,${_}$valueParamName"
-                : "$valueParamName";
-            var receiver = (setterCode & 1) ? "this" : "$receiverParamName";
-            var body = receiver + "." + field + "$_=$_$valueParamName";
-            var property =
-                cls + ".prototype.${namer.setterPrefix}" + accessorName + "=";
-            var fn = "function(" + args + "){" + body + "}";
-            if (reflectable)
-              accessors.push(property + "\$reflectable(" + fn + ");\\n");
-            else
-              accessors.push(property + fn + ";\\n");
-          }
-        }
+    // function generateAccessor(field, prototype, cls) {
+    jsAst.Fun fun = js.fun(['fieldDescriptor', 'accessors', 'cls'], [
+      js('var fieldInformation = fieldDescriptor.split("-")'),
+      js('var field = fieldInformation[0]'),
+      js('var len = field.length'),
+      js('var code = field.charCodeAt(len - 1)'),
+      js('var reflectable'),
+      js.if_('fieldInformation.length > 1', js('reflectable = true'),
+             js('reflectable = false')),
+      js('code = ((code >= $RANGE1_FIRST) && (code <= $RANGE1_LAST))'
+          '    ? code - $RANGE1_ADJUST'
+          '    : ((code >= $RANGE2_FIRST) && (code <= $RANGE2_LAST))'
+          '      ? code - $RANGE2_ADJUST'
+          '      : ((code >= $RANGE3_FIRST) && (code <= $RANGE3_LAST))'
+          '        ? code - $RANGE3_ADJUST'
+          '        : $NO_FIELD_CODE'),
+
+      // if (needsAccessor) {
+      js.if_('code', [
+        js('var getterCode = code & 3'),
+        js('var setterCode = code >> 2'),
+        js('var accessorName = field = field.substring(0, len - 1)'),
+
+        js('var divider = field.indexOf(":")'),
+        js.if_('divider > 0', [  // Colon never in first position.
+          js('accessorName = field.substring(0, divider)'),
+          js('field = field.substring(divider + 1)')
+        ]),
+
+        // if (needsGetter) {
+        js.if_('getterCode', [
+          js('var args = (getterCode & 2) ? "$receiverParamName" : ""'),
+          js('var receiver = (getterCode & 1) ? "this" : "$receiverParamName"'),
+          js('var body = "return " + receiver + "." + field'),
+          js('var property ='
+             ' cls + ".prototype.${namer.getterPrefix}" + accessorName + "="'),
+          js('var fn = "function(" + args + "){" + body + "}"'),
+          js.if_(
+              'reflectable',
+              js('accessors.push(property + "\$reflectable(" + fn + ");\\n")'),
+              js('accessors.push(property + fn + ";\\n")')),
+        ]),
+
+        // if (needsSetter) {
+        js.if_('setterCode', [
+          js('var args = (setterCode & 2)'
+              '  ? "$receiverParamName,${_}$valueParamName"'
+              '  : "$valueParamName"'),
+          js('var receiver = (setterCode & 1) ? "this" : "$receiverParamName"'),
+          js('var body = receiver + "." + field + "$_=$_$valueParamName"'),
+          js('var property ='
+             ' cls + ".prototype.${namer.setterPrefix}" + accessorName + "="'),
+          js('var fn = "function(" + args + "){" + body + "}"'),
+          js.if_(
+              'reflectable',
+              js('accessors.push(property + "\$reflectable(" + fn + ");\\n")'),
+              js('accessors.push(property + fn + ";\\n")')),
+        ]),
+
+      ]),
+
+      // return field;
+      js.return_('field')
+    ]);
 
-        return field;
-      }''');
+    return new jsAst.FunctionDeclaration(
+        new jsAst.VariableDeclaration('generateAccessor'),
+        fun);
   }
 
   List get defineClassFunction {
@@ -295,134 +304,130 @@ class CodeEmitterTask extends CompilerTask {
     // object and copy over the members.
 
     String reflectableField = namer.reflectableField;
+    List<jsAst.Node> statements = [
+      js('var pendingClasses = {}'),
+      js.if_('!init.allClasses', js('init.allClasses = {}')),
+      js('var allClasses = init.allClasses'),
+
+      optional(
+          DEBUG_FAST_OBJECTS,
+          js('print("Number of classes: "'
+             r' + Object.getOwnPropertyNames($$).length)')),
+
+      js('var hasOwnProperty = Object.prototype.hasOwnProperty'),
+
+      js.if_('typeof dart_precompiled == "function"',
+          [js('var constructors = dart_precompiled(collectedClasses)')],
+
+          [js('var combinedConstructorFunction = "function \$reflectable(fn){'
+              'fn.$reflectableField=1;return fn};\\n"+ "var \$desc;\\n"'),
+           js('var constructorsList = []')]),
+      js.forIn('cls', 'collectedClasses', [
+        js.if_('hasOwnProperty.call(collectedClasses, cls)', [
+          js('var desc = collectedClasses[cls]'),
+          js.if_('desc instanceof Array', js('desc = desc[1]')),
+
+          /* The 'fields' are either a constructor function or a
+           * string encoding fields, constructor and superclass.  Get
+           * the superclass and the fields in the format
+           *   '[name/]Super;field1,field2'
+           * from the CLASS_DESCRIPTOR_PROPERTY property on the descriptor.
+           * The 'name/' is optional and contains the name that should be used
+           * when printing the runtime type string.  It is used, for example, to
+           * print the runtime type JSInt as 'int'.
+           */
+           js('var classData = desc["${namer.classDescriptorProperty}"], '
+              'supr, name = cls, fields = classData'),
+          optional(
+              backend.hasRetainedMetadata,
+              js.if_('typeof classData == "object" && '
+                     'classData instanceof Array',
+                     [js('classData = fields = classData[0]')])),
+
+          js.if_('typeof classData == "string"', [
+            js('var split = classData.split("/")'),
+            js.if_('split.length == 2', [
+              js('name = split[0]'),
+              js('fields = split[1]')
+            ])
+          ]),
+
+          js('var s = fields.split(";")'),
+          js('fields = s[1] == "" ? [] : s[1].split(",")'),
+          js('supr = s[0]'),
+          js('split = supr.split(":")'),
+          js.if_('split.length == 2', [
+            js('supr = split[0]'),
+            js('var functionSignature = split[1]'),
+            js.if_('functionSignature',
+                js('desc.\$signature = #',
+                   js.fun('s',
+                       js.return_(js.fun([], js.return_('init.metadata[s]'))))(
+                           js('functionSignature'))))
+          ]),
+
+          optional(needsMixinSupport, js.if_('supr && supr.indexOf("+") > 0', [
+            js('s = supr.split("+")'),
+            js('supr = s[0]'),
+            js('var mixin = collectedClasses[s[1]]'),
+            js.if_('mixin instanceof Array', js('mixin = mixin[1]')),
+            js.forIn('d', 'mixin', [
+              js.if_('hasOwnProperty.call(mixin, d)'
+                     '&& !hasOwnProperty.call(desc, d)',
+                js('desc[d] = mixin[d]'))
+            ]),
+          ])),
+
+          js.if_('typeof dart_precompiled != "function"',
+              [js('combinedConstructorFunction +='
+                  ' defineClass(name, cls, fields)'),
+                 js('constructorsList.push(cls)')]),
+          js.if_('supr', js('pendingClasses[cls] = supr'))
+        ])
+      ]),
+      js.statement('''
+          if (typeof dart_precompiled != "function") {
+            combinedConstructorFunction +=
+               "return [\\n  " + constructorsList.join(",\\n  ") + "\\n]";
+             var constructors =
+              new Function("\$collectedClasses", combinedConstructorFunction)
+              (collectedClasses);
+            combinedConstructorFunction = null;
+          }'''),
+      js.for_('var i = 0', 'i < constructors.length', 'i++', [
+        js('var constructor = constructors[i]'),
+        js('var cls = constructor.name'),
+        js('var desc = collectedClasses[cls]'),
+        js('var globalObject = isolateProperties'),
+        js.if_('desc instanceof Array', [
+            js('globalObject = desc[0] || isolateProperties'),
+            js('desc = desc[1]')
+        ]),
+        optional(backend.isTreeShakingDisabled,
+                 js('constructor["${namer.metadataField}"] = desc')),
+        js('allClasses[cls] = constructor'),
+        js('globalObject[cls] = constructor'),
+      ]),
+      js('constructors = null'),
+
+      js('var finishedClasses = {}'),
+      js('init.interceptorsByTag = Object.create(null)'),
+      js('init.leafTags = {}'),
+
+      buildFinishClass(),
+    ];
 
-    return js('''
-      function(collectedClasses, isolateProperties, existingIsolateProperties) {
-        var pendingClasses = {};
-        if (!init.allClasses) init.allClasses = {};
-        var allClasses = init.allClasses;
-
-        if (#)  // DEBUG_FAST_OBJECTS
-          print("Number of classes: " +
-              Object.getOwnPropertyNames(\$\$).length);
-
-        var hasOwnProperty = Object.prototype.hasOwnProperty;
-
-        if (typeof dart_precompiled == "function") {
-          var constructors = dart_precompiled(collectedClasses);
-        } else {
-          var combinedConstructorFunction =
-             "function \$reflectable(fn){fn.$reflectableField=1;return fn};\\n"+
-             "var \$desc;\\n";
-          var constructorsList = [];
-        }
-
-        for (var cls in collectedClasses) {
-          if (hasOwnProperty.call(collectedClasses, cls)) {
-            var desc = collectedClasses[cls];
-            if (desc instanceof Array) desc = desc[1];
-
-            /* The 'fields' are either a constructor function or a
-             * string encoding fields, constructor and superclass.  Get
-             * the superclass and the fields in the format
-             *   '[name/]Super;field1,field2'
-             * from the CLASS_DESCRIPTOR_PROPERTY property on the descriptor.
-             * The 'name/' is optional and contains the name that should be used
-             * when printing the runtime type string.  It is used, for example,
-             * to print the runtime type JSInt as 'int'.
-             */
-            var classData = desc["${namer.classDescriptorProperty}"],
-                supr, name = cls, fields = classData;
-            if (#)  // backend.hasRetainedMetadata
-              if (typeof classData == "object" &&
-                  classData instanceof Array) {
-                classData = fields = classData[0];
-              }
-            if (typeof classData == "string") {
-              var split = classData.split("/");
-              if (split.length == 2) {
-                name = split[0];
-                fields = split[1];
-              }
-            }
-
-            var s = fields.split(";");
-            fields = s[1] == "" ? [] : s[1].split(",");
-            supr = s[0];
-            split = supr.split(":");
-            if (split.length == 2) {
-              supr = split[0];
-              var functionSignature = split[1];
-              if (functionSignature)
-                desc.\$signature = (function(s) {
-                    return function(){ return init.metadata[s]; };
-                  })(functionSignature);
-            }
-
-            if (#)  // needsMixinSupport
-              if (supr && supr.indexOf("+") > 0) {
-                s = supr.split("+");
-                supr = s[0];
-                var mixin = collectedClasses[s[1]];
-                if (mixin instanceof Array) mixin = mixin[1];
-                for(var d in mixin) {
-                  if (hasOwnProperty.call(mixin, d) &&
-                      !hasOwnProperty.call(desc, d))
-                    desc[d] = mixin[d];
-                }
-              }
-
-            if (typeof dart_precompiled != "function") {
-              combinedConstructorFunction += defineClass(name, cls, fields);
-              constructorsList.push(cls);
-            }
-            if (supr) pendingClasses[cls] = supr;
-          }
-        }
-
-        if (typeof dart_precompiled != "function") {
-          combinedConstructorFunction +=
-             "return [\\n  " + constructorsList.join(",\\n  ") + "\\n]";
-           var constructors =
-            new Function("\$collectedClasses", combinedConstructorFunction)
-            (collectedClasses);
-          combinedConstructorFunction = null;
-        }
-
-        for (var i = 0; i < constructors.length; i++) {
-          var constructor = constructors[i];
-          var cls = constructor.name;
-          var desc = collectedClasses[cls];
-          var globalObject = isolateProperties;
-          if (desc instanceof Array) {
-            globalObject = desc[0] || isolateProperties;
-            desc = desc[1];
-          }
-          if (#) //backend.isTreeShakingDisabled,
-            constructor["${namer.metadataField}"] = desc;
-          allClasses[cls] = constructor;
-          globalObject[cls] = constructor;
-        }
-
-        constructors = null;
-
-        var finishedClasses = {};
-        init.interceptorsByTag = Object.create(null);
-        init.leafTags = {};
-
-        #;  // buildFinishClass(),
+    nsmEmitter.addTrivialNsmHandlers(statements);
 
-        #;  // buildTrivialNsmHandlers()
+    statements.add(
+        js.statement('for (var cls in pendingClasses) finishClass(cls);')
+    );
 
-        for (var cls in pendingClasses) finishClass(cls);
-      }''', [
-          DEBUG_FAST_OBJECTS, 
-          backend.hasRetainedMetadata,
-          needsMixinSupport,
-          backend.isTreeShakingDisabled,
-          buildFinishClass(),
-          nsmEmitter.buildTrivialNsmHandlers()]);
- 
+    // function(collectedClasses,
+    //          isolateProperties,
+    //          existingIsolateProperties)
+    return js.fun(['collectedClasses', 'isolateProperties',
+                   'existingIsolateProperties'], statements);
   }
 
   jsAst.Node optional(bool condition, jsAst.Node node) {
@@ -432,35 +437,38 @@ class CodeEmitterTask extends CompilerTask {
   jsAst.FunctionDeclaration buildFinishClass() {
     String specProperty = '"${namer.nativeSpecProperty}"';  // "%"
 
-    return js.statement('''
-      function finishClass(cls) {
+    // function finishClass(cls) {
+    jsAst.Fun fun = js.fun(['cls'], [
 
-        // TODO(8540): Remove this work around.
-        // Opera does not support 'getOwnPropertyNames'. Therefore we use
-        //   hasOwnProperty instead.
-        var hasOwnProperty = Object.prototype.hasOwnProperty;
+      // TODO(8540): Remove this work around.
+      /* Opera does not support 'getOwnPropertyNames'. Therefore we use
+         hasOwnProperty instead. */
+      js('var hasOwnProperty = Object.prototype.hasOwnProperty'),
 
-        if (hasOwnProperty.call(finishedClasses, cls)) return;
+      // if (hasOwnProperty.call(finishedClasses, cls)) return;
+      js.if_('hasOwnProperty.call(finishedClasses, cls)',
+             js.return_()),
 
-        finishedClasses[cls] = true;
+      js('finishedClasses[cls] = true'),
 
-        var superclass = pendingClasses[cls];
+      js('var superclass = pendingClasses[cls]'),
 
-        // The superclass is only false (empty string) for the Dart Object
-        // class.  The minifier together with noSuchMethod can put methods on
-        // the Object.prototype object, and they show through here, so we check
-        // that we have a string.
-        if (!superclass || typeof superclass != "string") return;
-        finishClass(superclass);
-        var constructor = allClasses[cls];
-        var superConstructor = allClasses[superclass];
+      // The superclass is only false (empty string) for Dart's Object class.
+      // The minifier together with noSuchMethod can put methods on the
+      // Object.prototype object, and they show through here, so we check that
+      // we have a string.
+      js.if_('!superclass || typeof superclass != "string"', js.return_()),
+      js('finishClass(superclass)'),
+      js('var constructor = allClasses[cls]'),
+      js('var superConstructor = allClasses[superclass]'),
 
-        if (!superConstructor)
-          superConstructor = existingIsolateProperties[superclass];
+      js.if_(js('!superConstructor'),
+             js('superConstructor ='
+                    'existingIsolateProperties[superclass]')),
 
-        var prototype = inheritFrom(constructor, superConstructor);
+      js('var prototype = inheritFrom(constructor, superConstructor)'),
 
-        if (#) {  // !nativeClasses.isEmpty,
+      optional(!nativeClasses.isEmpty,
           // The property looks like this:
           //
           // HtmlElement: {
@@ -482,34 +490,30 @@ class CodeEmitterTask extends CompilerTask {
           //
           // The information is used to build tables referenced by
           // getNativeInterceptor and custom element support.
-          if (hasOwnProperty.call(prototype, $specProperty)) {
-            var nativeSpec = prototype[$specProperty].split(";");
-            if (nativeSpec[0]) {
-              var tags = nativeSpec[0].split("|");
-              for (var i = 0; i < tags.length; i++) {
-                init.interceptorsByTag[tags[i]] = constructor;
-                init.leafTags[tags[i]] = true;
-              }
-            }
-            if (nativeSpec[1]) {
-              tags = nativeSpec[1].split("|");
-              if (#) {  // User subclassing of native classes?
-                if (nativeSpec[2]) {
-                  var subclasses = nativeSpec[2].split("|");
-                  for (var i = 0; i < subclasses.length; i++) {
-                    var subclass = allClasses[subclasses[i]];
-                    subclass.\$nativeSuperclassTag = tags[0];
-                  }
-                }
-                for (i = 0; i < tags.length; i++) {
-                  init.interceptorsByTag[tags[i]] = constructor;
-                  init.leafTags[tags[i]] = false;
-                }
-              }
-            }
-          }
-        }
-      }''', [!nativeClasses.isEmpty, true]);
+          js.if_('hasOwnProperty.call(prototype, $specProperty)', [
+              js('var nativeSpec = prototype[$specProperty].split(";")'),
+              js.if_('nativeSpec[0]', [
+                  js('var tags = nativeSpec[0].split("|")'),
+                  js.for_('var i = 0', 'i < tags.length', 'i++', [
+                      js('init.interceptorsByTag[tags[i]] = constructor'),
+                      js('init.leafTags[tags[i]] = true')])]),
+              js.if_('nativeSpec[1]', [
+                  js('tags = nativeSpec[1].split("|")'),
+                  optional(true, // User subclassing of native classes?
+                      js.if_('nativeSpec[2]', [
+                          js('var subclasses = nativeSpec[2].split("|")'),
+                          js.for_('var i = 0', 'i < subclasses.length', 'i++', [
+                              js('var subclass = allClasses[subclasses[i]]'),
+                              js('subclass.\$nativeSuperclassTag = '
+                                 'tags[0]')])])),
+                  js.for_('i = 0', 'i < tags.length', 'i++', [
+                      js('init.interceptorsByTag[tags[i]] = constructor'),
+                      js('init.leafTags[tags[i]] = false')])])]))
+    ]);
+
+    return new jsAst.FunctionDeclaration(
+        new jsAst.VariableDeclaration('finishClass'),
+        fun);
   }
 
   jsAst.Fun get finishIsolateConstructorFunction {
@@ -536,57 +540,80 @@ class CodeEmitterTask extends CompilerTask {
         Isolate.prototype = oldIsolate.prototype;
         Isolate.prototype.constructor = Isolate;
         Isolate.${namer.isolatePropertiesName} = isolateProperties;
-        if (#)
-          Isolate.$finishClassesProperty = oldIsolate.$finishClassesProperty;
-        if (#)
-          Isolate.makeConstantList = oldIsolate.makeConstantList;
+        #
+        #
         return Isolate;
       }''',
-        [ needsDefineClass, hasMakeConstantList ]);
+      [ optional(needsDefineClass,
+            js('Isolate.$finishClassesProperty ='
+               ' oldIsolate.$finishClassesProperty')),
+        optional(hasMakeConstantList,
+            js('Isolate.makeConstantList = oldIsolate.makeConstantList'))
+      ]);
   }
 
   jsAst.Fun get lazyInitializerFunction {
+    // function(prototype, staticName, fieldName, getterName, lazyValue) {
+    var parameters = <String>['prototype', 'staticName', 'fieldName',
+                              'getterName', 'lazyValue'];
+    return js.fun(parameters, addLazyInitializerLogic());
+  }
+
+  List addLazyInitializerLogic() {
     String isolate = namer.currentIsolate;
     String cyclicThrow = namer.isolateAccess(backend.getCyclicThrowHelper());
+    var lazies = [];
+    if (backend.rememberLazies) {
+      lazies = [
+          js.if_('!init.lazies', js('init.lazies = {}')),
+          js('init.lazies[fieldName] = getterName')];
+    }
 
-    return js('''
-      function (prototype, staticName, fieldName, getterName, lazyValue) {
-        if (#) {
-          if (!init.lazies) init.lazies = {};
-          init.lazies[fieldName] = getterName;
-        }
-
-        var sentinelUndefined = {};
-        var sentinelInProgress = {};
-        prototype[fieldName] = sentinelUndefined;
-
-        prototype[getterName] = function () {
-          var result = $isolate[fieldName];
-          try {
-            if (result === sentinelUndefined) {
-              $isolate[fieldName] = sentinelInProgress;
-
-              try {
-                result = $isolate[fieldName] = lazyValue();
-              } finally {
-                // Use try-finally, not try-catch/throw as it destroys the
-                // stack trace.
-                if (result === sentinelUndefined)
-                  if ($isolate[fieldName] === sentinelInProgress)
-                    $isolate[fieldName] = null;
-              }
-            } else {
-              if (result === sentinelInProgress)
-                $cyclicThrow(staticName);
-            }
-
-            return result;
-          } finally {
-            $isolate[getterName] = function() { return this[fieldName]; };
-          }
-        }
-      }
-    ''', [backend.rememberLazies]);
+    return lazies..addAll([
+      js('var sentinelUndefined = {}'),
+      js('var sentinelInProgress = {}'),
+      js('prototype[fieldName] = sentinelUndefined'),
+
+      // prototype[getterName] = function()
+      js('prototype[getterName] = #', js.fun([], [
+        js('var result = $isolate[fieldName]'),
+
+        // try
+        js.try_([
+          js.if_('result === sentinelUndefined', [
+            js('$isolate[fieldName] = sentinelInProgress'),
+
+            // try
+            js.try_([
+              js('result = $isolate[fieldName] = lazyValue()'),
+
+            ], finallyPart: [
+              // Use try-finally, not try-catch/throw as it destroys the
+              // stack trace.
+
+              // if (result === sentinelUndefined)
+              js.if_('result === sentinelUndefined', [
+                // if ($isolate[fieldName] === sentinelInProgress)
+                js.if_('$isolate[fieldName] === sentinelInProgress', [
+                  js('$isolate[fieldName] = null'),
+                ])
+              ])
+            ])
+          ], /* else */ [
+            js.if_('result === sentinelInProgress',
+              js('$cyclicThrow(staticName)')
+            )
+          ]),
+
+          // return result;
+          js.return_('result')
+
+        ], finallyPart: [
+          js('$isolate[getterName] = #',
+             js.fun([], [js.return_('this[fieldName]')]))
+        ])
+      ]))
+    ]);
   }
 
   List buildDefineClassAndFinishClassFunctionsIfNecessary() {
@@ -601,7 +628,7 @@ class CodeEmitterTask extends CompilerTask {
   List buildLazyInitializerFunctionIfNecessary() {
     if (!needsLazyInitializer) return [];
 
-    return [js('# = #', [js(lazyInitializerName), lazyInitializerFunction])];
+    return [js('$lazyInitializerName = #', lazyInitializerFunction)];
   }
 
   List buildFinishIsolateConstructor() {
@@ -732,14 +759,15 @@ class CodeEmitterTask extends CompilerTask {
 
   jsAst.FunctionDeclaration buildPrecompiledFunction() {
     // TODO(ahe): Compute a hash code.
-    return js.statement('''
-      function dart_precompiled(\$collectedClasses) {
-        var \$desc;
-        #;
-        return #;
-      }''', [
-          precompiledFunction,
-          new jsAst.ArrayInitializer.from(precompiledConstructorNames)]);
+    String name = 'dart_precompiled';
+
+    precompiledFunction.add(
+        js.return_(
+            new jsAst.ArrayInitializer.from(precompiledConstructorNames)));
+    precompiledFunction.insert(0, js(r'var $desc'));
+    return new jsAst.FunctionDeclaration(
+        new jsAst.VariableDeclaration(name),
+        js.fun([r'$collectedClasses'], precompiledFunction));
   }
 
   void generateClass(ClassElement classElement, ClassBuilder properties) {
@@ -830,9 +858,8 @@ class CodeEmitterTask extends CompilerTask {
       compiler.withCurrentElement(element, () {
         Constant initialValue = handler.getInitialValueFor(element);
         jsAst.Expression init =
-          js('$isolateProperties.# = #',
-              [namer.getNameOfGlobalField(element),
-               constantEmitter.referenceInInitializationContext(initialValue)]);
+          js('$isolateProperties.${namer.getNameOfGlobalField(element)} = #',
+              constantEmitter.referenceInInitializationContext(initialValue));
         buffer.write(jsAst.prettyPrint(init, compiler));
         buffer.write('$N');
       });
@@ -856,15 +883,17 @@ class CodeEmitterTask extends CompilerTask {
         //   lazyInitializer(prototype, 'name', fieldName, getterName, initial);
         // The name is used for error reporting. The 'initial' must be a
         // closure that constructs the initial value.
+        List<jsAst.Expression> arguments = <jsAst.Expression>[];
+        arguments.add(js(isolateProperties));
+        arguments.add(js.string(element.name));
+        arguments.add(js.string(namer.getNameX(element)));
+        arguments.add(js.string(namer.getLazyInitializerName(element)));
+        arguments.add(code);
         jsAst.Expression getter = buildLazyInitializedGetter(element);
-        jsAst.Expression init = js('#(#,#,#,#,#,#)',
-            [js(lazyInitializerName),
-                js(isolateProperties),
-                js.string(element.name),
-                js.string(namer.getNameX(element)),
-                js.string(namer.getLazyInitializerName(element)),
-                code,
-                getter == null ? [] : [getter]]);
+        if (getter != null) {
+          arguments.add(getter);
+        }
+        jsAst.Expression init = js(lazyInitializerName)(arguments);
         buffer.write(jsAst.prettyPrint(init, compiler));
         buffer.write("$N");
       }
@@ -899,9 +928,9 @@ class CodeEmitterTask extends CompilerTask {
 
       String name = namer.constantName(constant);
       if (constant.isList) emitMakeConstantListIfNotEmitted(buffer);
-      jsAst.Expression init = js('#.# = #',
-          [namer.globalObjectForConstant(constant), name,
-           constantInitializerExpression(constant)]);
+      jsAst.Expression init = js(
+          '${namer.globalObjectForConstant(constant)}.$name = #',
+          constantInitializerExpression(constant));
       buffer.write(jsAst.prettyPrint(init, compiler));
       buffer.write('$N');
     }
@@ -1165,15 +1194,15 @@ class CodeEmitterTask extends CompilerTask {
   }
 
   void emitInitFunction(CodeBuffer buffer) {
-    jsAst.FunctionDeclaration decl = js.statement('''
-      function init() {
-        $isolateProperties = {};
-        #; #; #;
-      }''', [
-          buildDefineClassAndFinishClassFunctionsIfNecessary(),
-          buildLazyInitializerFunctionIfNecessary(),
-          buildFinishIsolateConstructor()]);
-
+    jsAst.Fun fun = js.fun([], [
+      js('$isolateProperties = {}'),
+    ]
+    ..addAll(buildDefineClassAndFinishClassFunctionsIfNecessary())
+    ..addAll(buildLazyInitializerFunctionIfNecessary())
+    ..addAll(buildFinishIsolateConstructor())
+    );
+    jsAst.FunctionDeclaration decl = new jsAst.FunctionDeclaration(
+        new jsAst.VariableDeclaration('init'), fun);
     buffer.write(jsAst.prettyPrint(decl, compiler).getText());
     if (compiler.enableMinification) buffer.write('\n');
   }
@@ -1360,7 +1389,7 @@ mainBuffer.add(r'''
           var map = new jsAst.ObjectInitializer(properties);
           mainBuffer.write(
               jsAst.prettyPrint(
-                  js.statement('init.mangledNames = #', map), compiler));
+                  js('init.mangledNames = #', map).toStatement(), compiler));
           if (compiler.enableMinification) {
             mainBuffer.write(';');
           }
@@ -1376,7 +1405,7 @@ mainBuffer.add(r'''
           var map = new jsAst.ObjectInitializer(properties);
           mainBuffer.write(
               jsAst.prettyPrint(
-                  js.statement('init.mangledGlobalNames = #', map),
+                  js('init.mangledGlobalNames = #', map).toStatement(),
                   compiler));
           if (compiler.enableMinification) {
             mainBuffer.write(';');