feat(transpiler): class fields for Dart

tools/transpiler/spec/classes_spec.js

@@ -49,6 +49,11 @@ class HasGetters {
   }
 }
 
+class WithFields {
+  name: string;
+  static id: number;
+}
+
 export function main() {
   describe('classes', function() {
     it('should work', function() {
@@ -89,6 +94,14 @@ export function main() {
         expect(HasGetters.staticGetter).toEqual('getter');
       });
     });
+
+    describe('fields', function() {
+      it('should work', function() {
+        var obj = new WithFields();
+        obj.name = 'Vojta';
+        WithFields.id = 12;
+      });
+    });
   });
 
 }

tools/transpiler/spec/types_spec.js

@@ -1,4 +1,4 @@
-import {describe, it, expect} from 'test_lib/test_lib';
+import {describe, it, expect, IS_DARTIUM} from 'test_lib/test_lib';
 
 class A {}
 class B {}
@@ -48,6 +48,12 @@ class Foo {
   }
 }
 
+class WithFields {
+  name: string;
+  static id: number;
+}
+
+
 export function main() {
   describe('types', function() {
     it('should work', function() {
@@ -58,5 +64,37 @@ export function main() {
 
       f.typedVariables();
     });
+
+    describe('class fields', function() {
+      it('should fail when setting wrong type value', function() {
+        var wf = new WithFields();
+
+        expect(function() {
+          wf.name = true;
+        }).toThrowError(IS_DARTIUM ?
+          // Dart
+          "type 'bool' is not a subtype of type 'String' of 'value'" :
+          // JavaScript
+          // TODO(vojta): Better error, it's not first argument, it's setting a field.
+          'Invalid arguments given!\n' +
+          '  - 1st argument has to be an instance of string, got true'
+        );
+      });
+    });
+
+    describe('static class fields', function() {
+      it('should fail when setting wrong type value', function() {
+        expect(function() {
+          WithFields.id = true;
+        }).toThrowError(IS_DARTIUM ?
+          // Dart
+          "type 'bool' is not a subtype of type 'num' of 'id'" :
+          // JavaScript
+          // TODO(vojta): Better error, it's not first argument, it's setting a field.
+          'Invalid arguments given!\n' +
+          '  - 1st argument has to be an instance of number, got true'
+        );
+      });
+    });
   });
-}
+}

tools/transpiler/src/outputgeneration/DartParseTreeWriter.js

@@ -32,6 +32,19 @@ export class DartParseTreeWriter extends JavaScriptParseTreeWriter {
     this.libName = moduleName.replace(/\//g, '.').replace(/[^\w.\/]/g, '_');
   }
 
+  // CLASS FIELDS
+  visitPropertyVariableDeclaration(tree) {
+    if (tree.isStatic) {
+      this.write_(STATIC);
+      this.writeSpace_();
+    }
+
+    this.writeType_(tree.typeAnnotation);
+    this.writeSpace_();
+    this.visitAny(tree.name);
+    this.write_(SEMI_COLON);
+  }
+
   // VARIABLES - types
   // ```
   // var foo:bool = true;