How to install an npm package from GitHub directly?

Question

Trying to install modules from github results in:

ENOENT error on package.json.

Easily reproduced using express:

Answer 1

Update September 2016

Installing from vanilla https github URLs now works:

npm install https://github.com/fergiemcdowall/search-index.git

EDIT 1: You can't do this for all modules because you are reading from a source control system, which may well contain invalid/uncompiled/buggy code. So to be clear (although it should go without saying): given that the code in the repo is in an npm-usable state, you can now quite happily install directly from github

EDIT 2: (21-10-2019) We are now living through "peak Typescript/React/Babel", and therefore JavaScript compilation has become quite common. If you need to take compilation into account look into prepare. That said, NPM modules do not need to be compiled, and it is wise to assume that compilation is not the default, especially for older node modules (and possibly also for very new, bleeding-edge "ESNext"-y ones).