Ambient Modules

Ambient Modules

In Node.js, most tasks are accomplished by loading one or more modules. We could define each module in its own .d.ts file with top-level export declarations, but it’s more convenient to write them as one larger .d.ts file. To do so, we use a construct similar to ambient namespaces, but we use the module keyword and the quoted name of the module which will be available to a later import. For example:

node.d.ts (simplified excerpt)

declare module "url" {
  export interface Url {
    protocol?: string;
    hostname?: string;
    pathname?: string;
  }

  export function parse(urlStr: string, parseQueryString?, slashesDenoteHost?): Url;
}

declare module "path" {
  export function normalize(p: string): string;
  export function join(...paths: any[]): string;
  export var sep: string;
}

Now we can /// <reference> node.d.ts and then load the modules using import url = require("url");.

/// <reference path="node.d.ts"/>
import * as URL from "url";
let myUrl = URL.parse("http://www.typescriptlang.org");