How to tell if a project uses Yarn

Question

How does one know if a project uses Yarn or NPM? Both contain a package.json file, although Yarn dependencies contain a file in the folder called yarn.lock.

Answer 1

I created this shell alias to detect if a project uses npm or yarn.

alias npm_or_yarn='ls yarn.lock &> /dev/null && echo yarn || echo npm'

You can also create an alias to automatically run start using npm or yarn.

alias npm_or_yarn_start='$(npm_or_yarn) start'