[javascript] Typescript es6 import module "File is not a module error"

I am using typescript 1.6 with es6 modules syntax.

My files are:

test.ts:

module App {
  export class SomeClass {
    getName(): string {
      return 'name';
    }
  }
}

main.ts:

import App from './test';

var a = new App.SomeClass();

When I am trying to compile the main.ts file I get this error:

Error TS2306: File 'test.ts' is not a module.

How can I accomplish that?

In addition to Tim's answer, this issue occurred for me when I was splitting up a refactoring a file, splitting it up into their own files.

VSCode, for some reason, indented parts of my [class] code, which caused this issue. This was hard to notice at first, but after I realised the code was indented, I formatted the code and the issue disappeared.

for example, everything after the first line of the Class definition was auto-indented during the paste.

export class MyClass extends Something<string> {
    public blah: string = null;

    constructor() { ... }
  }

How can I accomplish that?

Your example declares a TypeScript < 1.5 internal module, which is now called a namespace. The old module App {} syntax is now equivalent to namespace App {}. As a result, the following works:

// test.ts
export namespace App {
    export class SomeClass {
        getName(): string {
            return 'name';
        }
    }
}

// main.ts
import { App } from './test';
var a = new App.SomeClass();

That being said...

Try to avoid exporting namespaces and instead export modules (which were previously called external modules). If needs be you can use a namespace on import with the namespace import pattern like this:

// test.ts
export class SomeClass {
    getName(): string {
        return 'name';
    }
}

// main.ts
import * as App from './test'; // namespace import pattern
var a = new App.SomeClass();

In addition to A. Tim's answer there are times when even that doesn't work, so you need to:

1. Rewrite the import string, using the intellisense. Sometimes this fixes the issue
2. Restart VS Code

The file needs to add Component from core hence add the following import to the top

import { Component } from '@angular/core';

Above answers are correct. But just in case... Got same error in VS Code. Had to re-save/recompile file that was throwing error.