I was not able to install npm packages globally in mac os(using npm install -g), but able to install locally in the project. Installing locally in every project will increase the total node_modules folder size and for every project we need to install the same packages that will be tedious and unnecessary.
Here are the steps I performed.
I was using Homebrew to install node and npm. So,
Used command npm config get prefix – check where the npm actually points to. If this points to /opt/homebrew
Check if node_modules are installed in cd /usr/local/lib
If (2) is true, brew remove npm and then brew install npm
Now see if npm install -g express works