How to use Namespace Typescript properly with Webp

问题:

I am working on a new project with webpack. This is my first try with this tool.

I used to develop with typescript (for angularJS 1.5) since 1 year and I never had any problems relating to my namespacing.

// src/App/Core/Http/Test.ts
export namespace App.Core.Http {
      export class Test {
          public attr:any;
      }
 }

// src/App/Bootstrap.ts
import { App } from "./Core/Http/Test";
let testInstance = new App.Core.Http.Test();

What if I have more file to import. I can't import more than one "App" variable and I don't want to make alias each time I'm processing an import.

This is the case I don't want and I would like to fix :

// src/App/Bootstrap.ts
import { App } from "./Core/Http/Test";
import { App as App2 } from "./Core/Http/Test2"; // How can I import properly my namespace
let testInstance = new App.Core.Http.Test(),
    test2Instance = new App2.Core.Http.Test2();

Am I wrong with something or did I mess something about webpack ? How can I play with namespace like in PHP with webpack ?

回答1:

You should not be using namespaces and modules at the same time, even if you were not using webpack you would have the same problem

a normal approach with modules is to just export the class directly:

// src/App/Core/Http/Test.ts
export class Test {
    public attr:any;
}

// src/App/Bootstrap.ts
import { Test } from "./Core/Http/Test";
let testInstance = new Test();

the other example:

// src/App/Bootstrap.ts
import { Test} from "./Core/Http/Test";
import { Test2 } from "./Core/Http/Test2";
let testInstance = new Test(),
    test2Instance = new Test2();

hope this helps :)

回答2:

I learnt that it is not possible to use namespace using webpack. Why ? Because each .ts file are considered as a module with its own scope.

Module developement is required.

I've found a solution to get my file call clearer using module instead of namespace.

In my case, I have App/Core which contains Http, Service, Factory, Provider... folders. At the root of Core folder I created a index.ts file which export all my needed files with module architecture. Let's see.

// src/App/Core/index.ts
export module Http {
      export { Test } from "src/App/Core/Http/Test";
      export { Test2 } from "src/App/Core/Http/Test2";
      export { Test3 } from "src/App/Core/Http/Test3";
 }

export module Service {
      export { ServiceTest } from "src/App/Core/Service/ServiceTest";
      export { ServiceTest2 } from "src/App/Core/Service/ServiceTest2";
      export { ServiceTest3 } from "src/App/Core/Service/ServiceTest3";
}
//src/App/Core/index.ts ----> EOF 

And in another file call import the module with the alias Core.

// src/App/Bootstrap.ts
import { * as Core } from "./Core";

let TestInstance = new Core.Http.Test(),
    Test2Instance = new Core.Http.Test2(),
    TestInstance = new Core.Http.Test3();

let ServiceTestInstance = new Core.Service.Test(),
    ServiceTest2Instance = new Core.Service.Test2(),
    ServiceTestInstance = new Core.Service.Test3();

// src/App/Bootstrap.ts ----> EOF

回答3:

In TypeScript you can alias namespaces with another kind of import statement. It's pretty simple.

import { App } from "./Core/Http/Test";
import Test = App.Core.Http.Test;
import { App as App2 } from "./Core/Http/Test2";
import Test2 = App2.Core.Http.Test2;

At runtime, this is no different than const Test2 = App2.Core.Http.Test2; but at compile-time, using an import statement brings over all the type information, too.