JavaScript package managers
Tools that help you manage packages as dependencies and might also provide a global package registry
They work based on manifest files that keep track application metadata and needed dependencies, lock files to offer deterministic installs.
npm
npm is the most popular JavaScript package manager; it consists a website to discover packages, a CLI to interact with packages in terminal, and a global registry to share both private and pubic packages.
yarn
yarn is a JavaScript package manager released by Facebook in 2016, compatible with the npm registry; it focuses on building a CLI client that is super fast, secure, and deterministic.
pnpm
pnpm uses hard links and symlinks to save one version of a module only ever once on a disk. When using npm or Yarn for example, if you have 100 projects using the same version of lodash, you will have 100 copies of lodash on disk. With pnpm, lodash will be saved in a single place on the disk and a hard link will put it into the node_modules where it should be installed.
bower
bower is a package manager optimized for frontend; it can manage components that contain HTML, CSS, JavaScript, fonts or even image files. It keeps track packages in bower.json and puts installed packages in bower_components folder. It was created at the time npm only supported node packages, now fading away when both npm and yarn can support both node and browser packages with little help from module bundlers like Webpack or Browserify.