$ git clone git://github.com/oleavr/frida-agent-example.git
$ cd frida-agent-example/
$ npm install
$ frida -U -f com.example.android --no-pause -l _agent.js
To continuously recompile on change, keep this running in a terminal:
$ npm run watch
And use an editor like Visual Studio Code for code completion and instant type-checking feedback.