Visual Studio 2015 RC Typescript experimental decorators error

Visual Studio 2015 supports tsconfig files starting with Typescript version 1.8. Create tsconfig.json file at the root of your project and add experimentalDecorators compiler option.

Example:

{
  "compileOnSave": true,
  "compilerOptions": {
    "module": "commonjs",
    "sourceMap": true,

    "experimentalDecorators": true
  }
}

For older versions:

https://github.com/Microsoft/TypeScript/issues/3934

If you have a project file, tsconfig will not be honored. the project file takes precedence. We are still flushing the integration story between a VS project and a tsconfig as you can specify compiler options in both.

so to disable the error message, right-click on project file, unload project, then right-click edit the project file, At the end of the file there should be a config section, add:

<PropertyGroup Condition="'$(Configuration)' == 'Debug'">
  ....
  <TypeScriptExperimentalDecorators>true</TypeScriptExperimentalDecorators>
</PropertyGroup>

save and reload.

You may also need TypeScriptEmitDecoratorMetadata to map –emitDecroatorMetadata