Scott source at https://github.com/scottdurow/powerapps-pcf-samples/tree/master/PCFReactFieldDemo
pac pcf init --namespace dev1 --name calculator --template field
npm install eslint --save-dev
npm install --save-dev @typescript-eslint/eslint-plugin @typescript-eslint/parser eslint-plugin-react eslint-config-prettier eslint-plugin-prettier
npm install --save @fluentui/react react react-dom
npm install -save mobx mobx-react
npm install --save pcf-react (refer https://www.npmjs.com/package/pcf-react)
To run
npm start watch