Why can't node js see installed npm packages?

Question

Node.js

Hello, I'm not sure that I correctly formulated the question, there was such a problem. I'm trying to install an npm package, let's say postcss, the installation is successful, everything is fine, but as soon as I try to run this package, the console gives a bash error: <package name>: command not found. And so with all packages. It doesn't matter if I install the package globally or locally. Please tell me what could be the problem?

Answer 1

Option 1:

PATH="$PWD/node_modules/.bin:$PATH" postcss --params

Option 2:
write the command in the scripts section of package.json and run it via npm run

{
  "scripts": {
    "postcss": "postcss --params"
  }
}

npm run postcss
option 3:
run the package via npx, this does not even require installationnpx postcss --params

Answer 2

Install the package locally and run it from the folder where you installed it. Accordingly, do not forget to init npm.
If it works, dig for information about global paths in the system.