How to write a typescript definition file for a node module that exports a function?

Use export =.

Definition:

declare module 'glob' {
  function globs(paths: string, options: any, callback: (err: any, files: string[]) => void): any;
  export = globs;
}

Usage (with esModuleInterop enabled):

import glob from 'glob';
glob("*.js", {}, (err, files) => { });

Basarat's answer doesn't work with typescript 2.1.5. You need to declare function and export with export =:

export = MyFunction;
declare function MyFunction(): string;

How to write a definition file for commonjs module that exports function