Enable decorators in TS projects (codesandbox#386)

* Enable decorators in TS projects

* Allow decorators in TS editor

Author: CompuIves

packages/app/src/app/components/sandbox/CodeEditor/Monaco.js

@@ -626,7 +626,7 @@ export default class CodeEditor extends React.Component<Props, State> {
       module: hasNativeTypescript
         ? monaco.languages.typescript.ModuleKind.ES2015
         : monaco.languages.typescript.ModuleKind.System,
-      experimentalDecorators: !hasNativeTypescript,
+      experimentalDecorators: true,
       noEmit: true,
       allowJs: true,
       typeRoots: ['node_modules/@types'],

packages/app/src/sandbox/eval/transpilers/typescript/typescript-worker.js

@@ -42,6 +42,7 @@ self.addEventListener('message', event => {
       noUnusedLocals: true,
       inlineSourceMap: true,
       inlineSources: true,
+      experimentalDecorators: true,
     },
   };