add npm helper doc

docs/npm-misc/README.md

@@ -0,0 +1,53 @@
+# How to install NPM on Ubuntu 18.04
+
+The default `nodejs` package on Ubuntu installs an ancient version of Node/NPM
+that often doesn't work properly with contemporary code.
+
+As of the time of writing, Ubuntu's repository contains Node 8.10.0, which is 6
+years out of date.
+
+To install the latest version of Node (currently: 18.10.0)
+
+```
+sudo snap refresh
+sudo snap install node --channel 18/stable
+```
+
+You can use `snap info node` to get more information about the latest available
+versions.
+
+You can use `node --version` to verify you are running the most recent version
+of Node.
+
+```
+$ node --version
+v18.10.0
+```
+
+
+# How to install packages from NPM on unix without using `sudo`
+
+To install an executable package from NPM (such as the TypeScript compiler),
+you use `npm install -g PACKAGE`. By default, this attempts to install
+`PACKAGE` in a privileged directory, thus requiring `sudo` to execute
+successfully.
+
+In order to avoid running NPM as root, do the following:
+
+```
+mkdir ~/.npm-packages
+npm config set prefix "${HOME}/.npm-packages"
+```
+
+Edit `~/.bashrc` or `~/.zshrc` with
+
+```
+NPM_PACKAGES="${HOME}/.npm-packages"
+export PATH=$NPM_PACKAGES/bin:$PATH
+```
+
+Now, `npm install -g` will install to `~/.npm-packages`
+
+```
+npm install -g typescript
+```