Why does npm take so long while installing packages?

it takes ~5 minutes to download and install. Why is this happening? Are these node packages large in size?

Node Modules sometimes have many dependencies (other modules that are needed to run correctly). Often these dependent modules are used for different modules which may be used in your package.json so when they are downloaded/ installed multiple copies will be installed for each modules that requires them. This may seem verbose, but the reasoning is to separate concerns and to allow each module still able to function correctly. This means that individual modules, particularly those with other modules as dependencies, install each as needed. This is also following a fundamental idiom of programming for packaging, which has it's root in *nix, is to do one task, keep it DRY, and do it well.

If you happen to explore the node_modules directory after doing an npm install command, you will typically see many sub-directories for each module.

Installing modules globally may help here, but it will not help very much if you are planning to share what you create.

Also, I don't see any verbose logging while the package downloads. I only see the '/' rotating for indicating an ongoing process. Is that the default behaviour?

Yes it is, unless there is an error.