combining-the-command-pattern-with-state-pattern-in-java-script_5.js

registerCommand(
  'SET_BACKGROUND_COLOR',
  function onSetState({ backgroundColor }) {
    setState((prevState) => ({ ...prevState, backgroundColor }))
  },
)

registerCommand('NOTIFY_SUBSCRIBERS', function onNotifySubscribers(...args) {
  subscribers.forEach((fn) => fn(...args))
})

registerCommand('ADD_PROFILE', function onAddProfile(profile) {
  setState((prevState) => ({
    ...prevState,
    profiles: prevState.profiles.concat(profile),
  }))
})