have-it

The fastest NPM install does nothing because you already have it

If you have lots of local projects each with its own node_modules folder you probably already have a huge number of installed NPM packages. If you are offline or hate waiting, you can "install" a module from another folder into the current one using dummy "proxy" module. The setup is almost instant!

Watch in action: NPM vs Yarn vs have-it

Quick stats: installing lodash, debug and express takes NPM 5 seconds, yarn takes 3 seconds, and have-it takes 250ms (0.25 seconds)

Example

1. Install have-it globally with npm i -g have-it. This tool will be available under have and have-it names.

2. Set root folder for top level search. For example my projects are usually in $HOME/git folder. Thus I set export HAVE=$HOME/git. By default it will use $HOME value as the root.

   $HOME
     /git
       /projectA
         /node_modules
       /projectB
         /node_modules
       /projectC
         /node_modules
   

3. Install something with have <name>. For example

   $ time have lodash
   have-it lodash
   have 1 module(s)
   lodash@4.17.4
    
   real  0m0.240s

For comparison $ time npm i lodash prints real 0m1.909s - a speed up of 10 times!

You can pass typical NPM flags to save the installed version -S --save -D --save-dev.

Installing dependencies from package.json

Just run have to install dependencies from the package.json file.

Fallback

If a module cannot be found locally, have-it falls back to using npm install command.

How does it work?

have-it finds the module already installed and then creates in the local node_modules folder a dummy file that has main pointing at the found main file. For example, if lodash was found in folder /Users/gleb/projectX/node_modules/lodash the local dummy package will be

cat node_modules/lodash/package.json
{
  "name": "lodash",
  "main": "/Users/gleb/projectX/node_modules/lodash/lodash.js",
  "version": "4.17.4",
  "description": "fake module created by 'have-it' pointing at existing module"
}

Having actual dummy module like above works nicely with Node and its module loader.

Main features

Seems all use cases are already implemented: installing a specific version, saving version in package.json, etc.

• #8 save installed name version in package.json
• #9 respect package.json versions when installing
• #10 allow installing specific version from CLI have lodash@3.0.0
• #12 make symbolic links for each "bin" entry

Related projects

• copi - physically copies found package into this folder
• local-npm - Local and offline-first npm mirror (unmaintained)

FAQ

Why not use `npm link`

`npm link` is cumbersome and links a single package *version* globally

Why not use symbolic links?

Symbolic links do not work if the linked package needs to load another one of its own packages. For example `debug` requires `ms`. If we link to `debug` package folder, then Node module loader fails to find `ms`

Why not use local NPM proxy?

Because it is (relatively) hard

What happens in production / CI?

Nothing, you just use `npm install` there

Debugging

Run this tool with DEBUG=have-it have ... environment variable.

To run e2e test use npm run e2e

To avoid building a single "dist" file during local development, add a new alias to the package.json

{
  "bin": {
    "have-it": "dist/have-it.js",
    "have": "dist/have-it.js",
    "_have": "bin/_have-it.js"
  }
}

and use this alias for local work

npm link
_have lodash

Small print

Author: Gleb Bahmutov <[e-mail]> © 2017

• @bahmutov
• glebbahmutov.com
• blog

License: MIT - do anything with the code, but don't blame me if it does not work.

Support: if you find any problems with this module, email / tweet / open issue on Github

MIT License

Copyright (c) 2017 Gleb Bahmutov <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.