Using of TypeScript decorators caused errors

Question

I'm using TypeScript in new ASP.NET core project type.

We actively use decorators.

Unfortunately, that causes lot of errors in VS2015 output:

Error   TS1219  Experimental support for decorators is a feature that is subject to change in a future release.
Specify '--experimentalDecorators' to remove this warning.  
WebApplication2 d:\documents\visual studio 2015\Projects\WebApplication2\src\WebApplication2\wwwroot\sources\app.ts 9   Active

That is quite simple to get rid of these error messages in regular ASP.NET projects modifying *.csproj file.

But ASP.NET Core project does not use .csproj, it uses .xproj instead.

So, how to allow experimental TypeScript decorators support in VS2015 in ASP.NET Core project?

---

You may find simplest project which reproduces the problem in sample github rep

Answer 1

1. Right click on your project > Add > New Item.
2. Pick Client-side from the left hand menu.
3. Add a new TypeScript JSON Configuration File. Leave it as the default name of tsconfig.json.
4. Open tsconfig.json. In the complierOptions section, add "experimentalDecorators": true.
5. Remove "wwwroot" from the "exclude" section.
6. Build and enjoy.

Here is my tsconfig.json file for completeness:

{
  "compilerOptions": {
    "noImplicitAny": false,
    "noEmitOnError": true,
    "removeComments": false,
    "sourceMap": true,
    "target": "es5",
    "experimentalDecorators": true
  },
  "exclude": [
    "node_modules"
  ]
}