I have the React type definition file (that is declared using an external module). In my source files, I usually do:

import * as R from "react"

and can then happily use R.createElement(... etc in a strongly typed fashion.

What I want is to not have to import R in every file, and instead have it as a global declaration (yes, I'm willing to polute the global namespace with a few variables). I've tried:

import * as React from "react";
declare var R : React;

This doesn't work though, I get "Cannot find name 'React'". Is there another way to export the entire module as global?

Edit 1 - I should have made clearer: I'm interested in how to export a global type definition in a .d.ts file. So assume I've attached R to window already. Now I need typescript to know that R is of type React module.

instead have it as a global

There are two sides to this: global type declaration for typescript and global variable availability for JavaScript consumption.

Global Type Declaration

A .d.ts or a declaration only contributes to the global name declaration space if there is no root level import or export in the file. So have a file globalreact.d.ts which will be an edited version of https://github.com/borisyankov/DefinitelyTyped/blob/master/react/react.d.ts of the form declare module R (instead of declare module "react").

Global Variable Export

You need to put it on window in case of the browser. So do the following in a file makeReactGlobal.ts:

var R = require('react'); 
(<any>window).R = R

And then in your application main have this file a dependency to ensure that it executes before any of your other code.