events.js

var _ = require('../util')
var inDoc = _.inDoc

/**
 * Setup the instance's option events & watchers.
 * If the value is a string, we pull it from the
 * instance's methods by name.
 */

exports._initEvents = function () {
  var options = this.$options
  registerCallbacks(this, '$on', options.events)
  registerCallbacks(this, '$watch', options.watch)
}

/**
 * Register callbacks for option events and watchers.
 *
 * @param {Vue} vm
 * @param {String} action
 * @param {Object} hash
 */

function registerCallbacks (vm, action, hash) {
  if (!hash) return
  var handlers, key, i, j
  for (key in hash) {
    handlers = hash[key]
    if (_.isArray(handlers)) {
      for (i = 0, j = handlers.length; i < j; i++) {
        register(vm, action, key, handlers[i])
      }
    } else {
      register(vm, action, key, handlers)
    }
  }
}

/**
 * Helper to register an event/watch callback.
 *
 * @param {Vue} vm
 * @param {String} action
 * @param {String} key
 * @param {*} handler
 */

function register (vm, action, key, handler) {
  var type = typeof handler
  if (type === 'function') {
    vm[action](key, handler)
  } else if (type === 'string') {
    var methods = vm.$options.methods
    var method = methods && methods[handler]
    if (method) {
      vm[action](key, method)
    } else {
      _.warn(
        'Unknown method: "' + handler + '" when ' +
        'registering callback for ' + action +
        ': "' + key + '".'
      )
    }
  }
}

/**
 * Setup recursive attached/detached calls
 */

exports._initDOMHooks = function () {
  this.$on('hook:attached', onAttached)
  this.$on('hook:detached', onDetached)
}

/**
 * Callback to recursively call attached hook on children
 */

function onAttached () {
  this._isAttached = true
  this._children.forEach(callAttach)
  if (this._transCpnts) {
    this._transCpnts.forEach(callAttach)
  }
}

/**
 * Iterator to call attached hook
 * 
 * @param {Vue} child
 */

function callAttach (child) {
  if (!child._isAttached && inDoc(child.$el)) {
    child._callHook('attached')
  }
}

/**
 * Callback to recursively call detached hook on children
 */

function onDetached () {
  this._isAttached = false
  this._children.forEach(callDetach)
  if (this._transCpnts) {
    this._transCpnts.forEach(callDetach)
  }
}

/**
 * Iterator to call detached hook
 * 
 * @param {Vue} child
 */

function callDetach (child) {
  if (child._isAttached && !inDoc(child.$el)) {
    child._callHook('detached')
  }
}

/**
 * Trigger all handlers for a hook
 *
 * @param {String} hook
 */

exports._callHook = function (hook) {
  var handlers = this.$options[hook]
  if (handlers) {
    for (var i = 0, j = handlers.length; i < j; i++) {
      handlers[i].call(this)
    }
  }
  this.$emit('hook:' + hook)
}