I generally recommend using nvm [1] to install Node, it's certainly a painless way to get Node 5, then it's also easy to switch version later, or maybe downgrade to the LTS when you're doing 'work work' (`nvm use 4`).

Just remember to set a default, e.g. if you're mostly using Node for Phoenix: `nvm alias default 5`.

It also sets up your global modules directory so that you don't need sudo to install global modules like gulp-cli (should you need any, though it's quite rare that you do nowadays).

[1] https://github.com/creationix/nvm

Phoenix needs NodeJS for the asset pipeline of the frontend.

Ah I see, why does Phoenix require Node 5?