Depend on a branch or tag using a git URL in a package.json?

If you want to use devel or feature branch, or you haven’t published a certain package to the NPM registry, or you can’t because it’s a private module, then you can point to a git:// URI instead of a version number in your package.json:

"dependencies": {
   "public": "git://github.com/user/repo.git#ref",
   "private": "git+ssh://[email protected]:user/repo.git#ref"
}

The #ref portion is optional, and it can be a branch (like master), tag (like 0.0.1) or a partial or full commit id.

From the npm docs, using a git URL:

git://github.com/<user>/<project>.git#<branch>

git://github.com/<user>/<project>.git#feature\/<branch>

As of NPM version 1.1.65, you can use a shorten github URL:

<user>/<project>#<branch>

UPDATE 2022

Don't use git:// protocol for GitHub, as it is not supported

npm ERR!   The unauthenticated git protocol on port 9418 is no longer supported.
npm ERR! Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.

per @dantheta's comment:

As of npm 1.1.65, Github URL can be more concise user/project. npmjs.org/doc/files/package.json.html You can attach the branch like user/project#branch

So

"babel-eslint": "babel/babel-eslint",

Or for tag v1.12.0 on jscs:

"jscs": "jscs-dev/node-jscs#v1.12.0",

Note, if you use npm --save, you'll get the longer git

From https://docs.npmjs.com/cli/v6/configuring-npm/package-json#git-urls-as-dependencies

Git URLs as Dependencies

Git urls are of the form:

git+ssh://[email protected]:npm/cli.git#v1.0.27 git+ssh://[email protected]:npm/cli#semver:^5.0 git+https://[email protected]/npm/cli.git
git://github.com/npm/cli.git#v1.0.27

If #<commit-ish> is provided, it will be used to clone exactly that commit. If > the commit-ish has the format #semver:<semver>, <semver> can be any valid semver range or exact version, and npm will look for any tags or refs matching that range in the remote repository, much as it would for a registry dependency. If neither #<commit-ish> or #semver:<semver> is specified, then master is used.

GitHub URLs

As of version 1.1.65, you can refer to GitHub urls as just "foo": "user/foo-project". Just as with git URLs, a commit-ish suffix can be included. For example:

{
 "name": "foo",
 "version": "0.0.0",
 "dependencies": {
   "express": "expressjs/express",
   "mocha": "mochajs/mocha#4727d357ea",
   "module": "user/repo#feature\/branch"
 }
}```