dependency vs devDependencies vs peerDependencies

They are how we define dependencies in Javascript-based projects

"dependencies": Packages required by your application in production.

"devDependencies": Packages that are only needed for local development and testing. NPM won’t install them when someone installs our dependency.

"peerDependencies": When someone installs our package, our package expects theirs to have these dependencies. If they don’t have it, NPM will still install them

Watch the video for more explanation