define sync & async redux actions

actions.js

// Useful for defining a standard synchronous action
exports.defineAction = function (actions, definition) {
  var {name, type} = definition

  var [actionFn, notification] = parseActionProps(definition)

  // pass in `type` via `this` context object
  var actionWrapper = function () {
    var context = {
      type: type
    }
    return actionFn.apply(context, arguments)
  }
  actionWrapper.type = type
  actionWrapper.notification = notification

  actions[name] = actionWrapper

  // return action fn
  return actionWrapper
}

// Useful for defining a standard async action that has a corresponding success/failure action
exports.defineAsyncActions = function (actions, definition) {
  var {name, type} = definition

  // normalize success/failure action definitions, add `name` & `type`
  var success = exports.defineAction(actions, {
    ...(typeof definition.success === 'function' ? { action: definition.success } : definition.success),
    name: name + 'Success',
    type: type + '.' + 'SUCCESS'
  })

  var failure = exports.defineAction(actions, {
    ...(typeof definition.failure === 'function' ? { action: definition.failure } : definition.failure),
    name: name + 'Failure',
    type: type + '.' + 'FAILURE'
  })

  // main action
  var [actionFn, notification] = parseActionProps(definition.action)
  actions[name] = function () {
    var originalArgs = arguments

    return function (dispatch, getState) {
      var context = {
        type,
        success,
        failure,
        dispatch,
        getState
      }
      return actionFn.apply(context, originalArgs)
    }
  }
  actions[name].type = definition.type
  actions[name].notification = notification

  // retrurn main async action
  return actions[name]
}

function parseActionProps (action) {
  var actionFn = typeof action === 'function' ? action : action.action
  var notification = action.notification

  if (!actionFn || typeof actionFn !== 'function') {
    throw new Error('Invalid action definition for ' + action.name)
  }

  // TODO: consider returning an object as new props are added
  return [actionFn, notification]
}