namespaced-model.js

export function namespacedModel (app, obj = {}) {
  const namespace = obj.namespace
  // TODO: assert that namespace was provided

  const initialState = obj.state || {}
  const reducers = obj.reducers || {}
  const effects = obj.effects || {}
  const subscriptions = obj.subscriptions || []

  const processedEffects = Object.keys(effects).reduce((o, effectName) => {
    const eff = effects[effectName]
    o[effectName] = (data, state, send) => eff(data, state, wrapSend(namespace, send))
    return o
  }, {})

  const processedSubscriptions = Object.keys(subscriptions).reduce((o, subName) => {
    const sub = subscriptions[subName]
    o[subName] = (send, done) => sub(wrapSend(namespace, send), done)
    return o
  }, {})

  app.model({
    namespace,
    state: initialState,
    reducers,
    effects: processedEffects,
    subscriptions: processedSubscriptions
  })
}

function wrapSend (namespace, send) {
  return function (actionName, ...args) {
    if (actionName.startsWith('::')) {
      // if it begins with two colons, then it's a top level single word action name
      actionName = actionName.substr(2)
      return send(actionName, ...args)
    } else if (actionName.match(/:/)) {
      // if it has a colon, then let it pass through as a global send
      return send(actionName, ...args)
    } else {
      // else namespace it
      return send(`${namespace}:${actionName}`, ...args)
    }
  }
}