Need to support declaration merging in external modules #2821
Description
jQuery (jQuery UI) support method extensions. If we write my own jQuery UI widget, I can do this:
In myWidget.ts:
interface JQuery { myWidget(): JQuery } class myWidget { public foo() { // This is okay now, but will fail once we add some import statements to this file, // because TypeScript thinks this JQuery is not that JQuery var some: JQuery = $("#some-id").text(); } } $.fn.extend({ myWidget() {...} });Then in another file:
$(selector).myWidget(); // Create a new myWidget, this is okay because of myWidget() is declared in my version of JQuery interface $(selector).attr("id", "my-id"); // This is okay because attr is declared in jquery.d.tsHowever, this stops working when I add this line to myWidget.ts:
import helpers = require("helpers");Now TypeScript thinks there 2 JQuery interfaces, instead of merging them into one. How do I tell TypeScript that I'm not creating a new interface for this module, but need to merge it with an existing interface?