Lost my now-tv remote and had had enough of the adverts on the mobile apps so had a quick look to find the now-tv boxes IP, found the roku docs (https://sdkdocs.roku.com/display/sdkdoc/External+Control+API#ExternalControlAPI-KeypressKeyValues) and quickly knocked up a working remote.
You will need to know the IP of the now-tv box, which you can find with nmap or by logging into your router's admin page.
A Vue.js project
# install dependencies
npm install
# Change box's IP
# sed -i 's/192.168.0.2/<YOUR_BOX_IP>/' ./src/config/index.json
sed -i '' 's/192.168.0.2/<YOUR_BOX_IP>/' ./src/config/index.json
# serve with hot reload at localhost:8080
npm run dev
# build for production with minification
npm run build
# build for production and view the bundle analyzer report
npm run build --report
For a detailed explanation on how things work, check out the guide and docs for vue-loader.