interface + new vs class + constructor in TypeScript

Question

In a *.d.ts file what is the difference between:

declare module "m1" {
}

and

declare module m1 {
}

?

Also what is the difference between:

declare module "m1" {
    export class c1 {
        constructor(value: string);
    }
} 

and

declare module "m1" {
    export interface c1 {
        new(value: string);
    }
}

Answer 1

The only different with module names in quotes is that they can only be used in ambient declarations. When you use a quoted name, you are describing a module that would be module-loaded (using require).

The difference between the class and the interface is that with the class you will be allowed to create new instances directly:

var instance = new m1.c1('val');

With the interface, you would need to additionally supply a variable that was typed to the interface in order to create a new one:

declare module m1 {
    interface c1 {
        new(value: string);
    }

    var example: m1.c1;
} 

// Not allowed
// var instance = new m1.c1('val');

// Allowed
var instance = new m1.example('val');

Using new m1.c1('val') will get you the error:

The property 'c1' does not exist on value of type 'typeof m1'.