This article is for people experiencing issues installing packages in emacs getting the following error:
error: Package "prettier-js" is unavailable
If you look in the *Messages* buffer you will see errors about the package archive you are pulling from, such as MELPA. These errors will complain about being unable to establish a secure connection to the MELPA servers. The reason for this is that the Emacs binaries available for Mac OSX don't come linked with the right version of gnutls. Emacs needs an updated version of gnutls to be able to establish a secure connection to MELPA's servers. If you have Homebrew, simply run the following command:
brew install gnutls
Relevant links: