npm install: Use global package if it exists, rather than installing twice

Question

When using npm install with a package.json file, how do I get it to use a globally installed package that meets the criteria instead of downloading and

Answer 1

One way of doing it for a specific set of modules is removing these modules from the dependencies section and creating a prestart script that contains all the modules that you prefer having installed globally.

A simple example might look something like this:

  "scripts": {
    "test": "mocha",
    "prestart": "npm i -g mocha mysql bluebird"
  },

Instead of prestart you can use one of the other hooks such as preinstall and prepare. Note that this won't work as-is with packages you want to publish and would require a bit more hacking.

Help on running scriipts: https://docs.npmjs.com/misc/scripts

Answer 2

Yarn seems to work much better with repeated dependencies. So try yarn install instead of npm install.