run.ts

import {hello} from './src/test';

hello();

src_test.d.ts

// Save in src/test.d.ts

declare module test {
	export var hello: any;
}

export = test;

// This also works, replacing all of the above:
// export declare var hello: any;

src_test.js

// Save in src/test.js

exports.hello = function () { console.log('Hello, World!'); };

tsconfig.json

{
	"compilerOptions": {
		"module": "commonjs",
		"noImplicitAny": true,
		"target": "es5"
	},
	"files": [
		"run.ts"
	]
}