npm, npx, and yarn. Which one is better?

I can see create-react-app has added installation with npx.

So it made me curious to check these package npm, npx and yarn.

Which one is better to use and why?

npm: Is used for installation of packages (libraries), i.e. pieces of functionality to help you build your own applications.

npm website and project github repository states that

• npm is a JavaScript package manager, just like: pip (Python), Maven (Java), NuGet (.NET), Composer (PHP), RubyGems (Ruby), ...
• Contrary to popular belief, npm is not in fact an acronym for "Node Package Manager"
• npm is the package manager for Node.js.
• Help JavaScript developers easily share packaged modules of code.
• npm is the command line client that allows developers to install and publish those packages.
• The npm Registry is a public collection of packages of open-source code for Node.js, front-end web apps, mobile apps, robots, routers, and countless other needs of the JavaScript community.

npx: npx is a tool to execute packages without installing the packages.

yarn: also installation of packages. yarn is a replacement for npm that sits on top of the same packages repository.

nvm: Node Version Manager, also there is nvm script which is used to install and management different version of node in a system.