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node_modules/vue-lazyload/src/index.js

@@ -0,0 +1,73 @@
+import Lazy from './lazy'
+import LazyComponent from './lazy-component'
+import LazyContainer from './lazy-container'
+import { assign } from './util'
+
+export default {
+  /*
+  * install function
+  * @param  {Vue} Vue
+  * @param  {object} options  lazyload options
+  */
+  install (Vue, options = {}) {
+    const LazyClass = Lazy(Vue)
+    const lazy = new LazyClass(options)
+    const lazyContainer = new LazyContainer({ lazy })
+
+    const isVue2 = Vue.version.split('.')[0] === '2'
+
+    Vue.prototype.$Lazyload = lazy
+
+    if (options.lazyComponent) {
+      Vue.component('lazy-component', LazyComponent(lazy))
+    }
+
+    if (isVue2) {
+      Vue.directive('lazy', {
+        bind: lazy.add.bind(lazy),
+        update: lazy.update.bind(lazy),
+        componentUpdated: lazy.lazyLoadHandler.bind(lazy),
+        unbind: lazy.remove.bind(lazy)
+      })
+      Vue.directive('lazy-container', {
+        bind: lazyContainer.bind.bind(lazyContainer),
+        update: lazyContainer.update.bind(lazyContainer),
+        unbind: lazyContainer.unbind.bind(lazyContainer)
+      })
+    } else {
+      Vue.directive('lazy', {
+        bind: lazy.lazyLoadHandler.bind(lazy),
+        update (newValue, oldValue) {
+          assign(this.vm.$refs, this.vm.$els)
+          lazy.add(this.el, {
+            modifiers: this.modifiers || {},
+            arg: this.arg,
+            value: newValue,
+            oldValue: oldValue
+          }, {
+            context: this.vm
+          })
+        },
+        unbind () {
+          lazy.remove(this.el)
+        }
+      })
+
+      Vue.directive('lazy-container', {
+        update (newValue, oldValue) {
+          lazyContainer.update(this.el, {
+            modifiers: this.modifiers || {},
+            arg: this.arg,
+            value: newValue,
+            oldValue: oldValue
+          }, {
+            context: this.vm
+          })
+        },
+        unbind () {
+          lazyContainer.unbind(this.el)
+        }
+      })
+    }
+  }
+}

node_modules/vue-lazyload/src/lazy-component.js

@@ -0,0 +1,52 @@
+import { inBrowser } from './util'
+
+export default (lazy) => {
+  return {
+    props: {
+      tag: {
+        type: String,
+        default: 'div'
+      }
+    },
+    render (h) {
+      if (this.show === false) {
+        return h(this.tag)
+      }
+      return h(this.tag, null, this.$slots.default)
+    },
+    data () {
+      return {
+        el: null,
+        state: {
+          loaded: false
+        },
+        rect: {},
+        show: false
+      }
+    },
+    mounted () {
+      this.el = this.$el
+      lazy.addLazyBox(this)
+      lazy.lazyLoadHandler()
+    },
+    beforeDestroy () {
+      lazy.removeComponent(this)
+    },
+    methods: {
+      getRect () {
+        this.rect = this.$el.getBoundingClientRect()
+      },
+      checkInView () {
+        this.getRect()
+        return inBrowser &&
+                    (this.rect.top < window.innerHeight * lazy.options.preLoad && this.rect.bottom > 0) &&
+                    (this.rect.left < window.innerWidth * lazy.options.preLoad && this.rect.right > 0)
+      },
+      load () {
+        this.show = true
+        this.state.loaded = true
+        this.$emit('show', this)
+      }
+    }
+  }
+}

node_modules/vue-lazyload/src/lazy-container.js

@@ -0,0 +1,78 @@
+import {
+  find,
+  remove,
+  assign,
+  ArrayFrom
+} from './util'
+
+export default class LazyContainerMananger {
+  constructor ({ lazy }) {
+    this.lazy = lazy
+    lazy.lazyContainerMananger = this
+    this._queue = []
+  }
+
+  bind (el, binding, vnode) {
+    const container = new LazyContainer({ el, binding, vnode, lazy: this.lazy })
+    this._queue.push(container)
+  }
+
+  update (el, binding, vnode) {
+    const container = find(this._queue, item => item.el === el)
+    if (!container) return
+    container.update({ el, binding, vnode })
+  }
+
+  unbind (el, binding, vnode) {
+    const container = find(this._queue, item => item.el === el)
+    if (!container) return
+    container.clear()
+    remove(this._queue, container)
+  }
+}
+
+const defaultOptions = {
+  selector: 'img'
+}
+
+class LazyContainer {
+  constructor ({ el, binding, vnode, lazy }) {
+    this.el = null
+    this.vnode = vnode
+    this.binding = binding
+    this.options = {}
+    this.lazy = lazy
+
+    this._queue = []
+    this.update({ el, binding })
+  }
+
+  update ({ el, binding }) {
+    this.el = el
+    this.options = assign({}, defaultOptions, binding.value)
+
+    const imgs = this.getImgs()
+    imgs.forEach(el => {
+      this.lazy.add(el, assign({}, this.binding, {
+        value: {
+          src: el.dataset.src,
+          error: el.dataset.error,
+          loading: el.dataset.loading
+        }
+      }), this.vnode)
+    })
+  }
+
+  getImgs () {
+    return ArrayFrom(this.el.querySelectorAll(this.options.selector))
+  }
+
+  clear () {
+    const imgs = this.getImgs()
+    imgs.forEach(el => this.lazy.remove(el))
+
+    this.vnode = null
+    this.binding = null
+    this.lazy = null
+  }
+}

node_modules/vue-lazyload/src/lazy.js

@@ -0,0 +1,443 @@
+import {
+  inBrowser,
+  CustomEvent,
+  remove,
+  some,
+  find,
+  _,
+  throttle,
+  supportWebp,
+  getDPR,
+  scrollParent,
+  getBestSelectionFromSrcset,
+  assign,
+  isObject,
+  hasIntersectionObserver,
+  modeType
+} from './util'
+
+import ReactiveListener from './listener'
+
+const DEFAULT_URL = 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7'
+const DEFAULT_EVENTS = ['scroll', 'wheel', 'mousewheel', 'resize', 'animationend', 'transitionend', 'touchmove']
+const DEFAULT_OBSERVER_OPTIONS = {
+  rootMargin: '0px',
+  threshold: 0
+}
+
+export default function (Vue) {
+  return class Lazy {
+    constructor ({ preLoad, error, throttleWait, preLoadTop, dispatchEvent, loading, attempt, silent = true, scale, listenEvents, hasbind, filter, adapter, observer, observerOptions }) {
+      this.version = '__VUE_LAZYLOAD_VERSION__'
+      this.mode = modeType.event
+      this.ListenerQueue = []
+      this.TargetIndex = 0
+      this.TargetQueue = []
+      this.options = {
+        silent: silent,
+        dispatchEvent: !!dispatchEvent,
+        throttleWait: throttleWait || 200,
+        preLoad: preLoad || 1.3,
+        preLoadTop: preLoadTop || 0,
+        error: error || DEFAULT_URL,
+        loading: loading || DEFAULT_URL,
+        attempt: attempt || 3,
+        scale: scale || getDPR(scale),
+        ListenEvents: listenEvents || DEFAULT_EVENTS,
+        hasbind: false,
+        supportWebp: supportWebp(),
+        filter: filter || {},
+        adapter: adapter || {},
+        observer: !!observer,
+        observerOptions: observerOptions || DEFAULT_OBSERVER_OPTIONS
+      }
+      this._initEvent()
+
+      this.lazyLoadHandler = throttle(this._lazyLoadHandler.bind(this), this.options.throttleWait)
+
+      this.setMode(this.options.observer ? modeType.observer : modeType.event)
+    }
+
+    /**
+     * update config
+     * @param  {Object} config params
+     * @return
+     */
+    config (options = {}) {
+      assign(this.options, options)
+    }
+
+    /**
+     * output listener's load performance
+     * @return {Array}
+     */
+    performance () {
+      let list = []
+
+      this.ListenerQueue.map(item => {
+        list.push(item.performance())
+      })
+
+      return list
+    }
+
+    /*
+     * add lazy component to queue
+     * @param  {Vue} vm lazy component instance
+     * @return
+     */
+    addLazyBox (vm) {
+      this.ListenerQueue.push(vm)
+      if (inBrowser) {
+        this._addListenerTarget(window)
+        this._observer && this._observer.observe(vm.el)
+        if (vm.$el && vm.$el.parentNode) {
+          this._addListenerTarget(vm.$el.parentNode)
+        }
+      }
+    }
+
+    /*
+     * add image listener to queue
+     * @param  {DOM} el
+     * @param  {object} binding vue directive binding
+     * @param  {vnode} vnode vue directive vnode
+     * @return
+     */
+    add (el, binding, vnode) {
+      if (some(this.ListenerQueue, item => item.el === el)) {
+        this.update(el, binding)
+        return Vue.nextTick(this.lazyLoadHandler)
+      }
+
+      let { src, loading, error } = this._valueFormatter(binding.value)
+
+      Vue.nextTick(() => {
+        src = getBestSelectionFromSrcset(el, this.options.scale) || src
+        this._observer && this._observer.observe(el)
+
+        const container = Object.keys(binding.modifiers)[0]
+        let $parent
+
+        if (container) {
+          $parent = vnode.context.$refs[container]
+          // if there is container passed in, try ref first, then fallback to getElementById to support the original usage
+          $parent = $parent ? $parent.$el || $parent : document.getElementById(container)
+        }
+
+        if (!$parent) {
+          $parent = scrollParent(el)
+        }
+
+        const newListener = new ReactiveListener({
+          bindType: binding.arg,
+          $parent,
+          el,
+          loading,
+          error,
+          src,
+          elRenderer: this._elRenderer.bind(this),
+          options: this.options
+        })
+
+        this.ListenerQueue.push(newListener)
+
+        if (inBrowser) {
+          this._addListenerTarget(window)
+          this._addListenerTarget($parent)
+        }
+
+        this.lazyLoadHandler()
+        Vue.nextTick(() => this.lazyLoadHandler())
+      })
+    }
+
+    /**
+    * update image src
+    * @param  {DOM} el
+    * @param  {object} vue directive binding
+    * @return
+    */
+    update (el, binding) {
+      let { src, loading, error } = this._valueFormatter(binding.value)
+      src = getBestSelectionFromSrcset(el, this.options.scale) || src
+
+      const exist = find(this.ListenerQueue, item => item.el === el)
+
+      exist && exist.update({
+        src,
+        loading,
+        error
+      })
+      if(this._observer){
+        this._observer.unobserve(el)
+        this._observer.observe(el)
+      }
+      this.lazyLoadHandler()
+      Vue.nextTick(() => this.lazyLoadHandler())
+    }
+
+    /**
+    * remove listener form list
+    * @param  {DOM} el
+    * @return
+    */
+    remove (el) {
+      if (!el) return
+      this._observer && this._observer.unobserve(el)
+      const existItem = find(this.ListenerQueue, item => item.el === el)
+      if (existItem) {
+        this._removeListenerTarget(existItem.$parent)
+        this._removeListenerTarget(window)
+        remove(this.ListenerQueue, existItem) && existItem.destroy()
+      }
+    }
+
+    /*
+     * remove lazy components form list
+     * @param  {Vue} vm Vue instance
+     * @return
+     */
+    removeComponent (vm) {
+      if (!vm) return
+      remove(this.ListenerQueue, vm)
+      this._observer && this._observer.unobserve(vm.el)
+      if (vm.$parent && vm.$el.parentNode) {
+        this._removeListenerTarget(vm.$el.parentNode)
+      }
+      this._removeListenerTarget(window)
+    }
+
+    setMode (mode) {
+      if (!hasIntersectionObserver && mode === modeType.observer) {
+        mode = modeType.event
+      }
+
+      this.mode = mode // event or observer
+
+      if (mode === modeType.event) {
+        if (this._observer) {
+          this.ListenerQueue.forEach(listener => {
+            this._observer.unobserve(listener.el)
+          })
+          this._observer = null
+        }
+
+        this.TargetQueue.forEach(target => {
+          this._initListen(target.el, true)
+        })
+      } else {
+        this.TargetQueue.forEach(target => {
+          this._initListen(target.el, false)
+        })
+        this._initIntersectionObserver()
+      }
+    }
+
+    /*
+    *** Private functions ***
+    */
+
+    /*
+     * add listener target
+     * @param  {DOM} el listener target
+     * @return
+     */
+    _addListenerTarget (el) {
+      if (!el) return
+      let target = find(this.TargetQueue, target => target.el === el)
+      if (!target) {
+        target = {
+          el: el,
+          id: ++this.TargetIndex,
+          childrenCount: 1,
+          listened: true
+        }
+        this.mode === modeType.event && this._initListen(target.el, true)
+        this.TargetQueue.push(target)
+      } else {
+        target.childrenCount++
+      }
+      return this.TargetIndex
+    }
+
+    /*
+     * remove listener target or reduce target childrenCount
+     * @param  {DOM} el or window
+     * @return
+     */
+    _removeListenerTarget (el) {
+      this.TargetQueue.forEach((target, index) => {
+        if (target.el === el) {
+          target.childrenCount--
+          if (!target.childrenCount) {
+            this._initListen(target.el, false)
+            this.TargetQueue.splice(index, 1)
+            target = null
+          }
+        }
+      })
+    }
+
+    /*
+     * add or remove eventlistener
+     * @param  {DOM} el DOM or Window
+     * @param  {boolean} start flag
+     * @return
+     */
+    _initListen (el, start) {
+      this.options.ListenEvents.forEach((evt) => _[start ? 'on' : 'off'](el, evt, this.lazyLoadHandler))
+    }
+
+    _initEvent () {
+      this.Event = {
+        listeners: {
+          loading: [],
+          loaded: [],
+          error: []
+        }
+      }
+
+      this.$on = (event, func) => {
+        this.Event.listeners[event].push(func)
+      }
+
+      this.$once = (event, func) => {
+        const vm = this
+        function on () {
+          vm.$off(event, on)
+          func.apply(vm, arguments)
+        }
+        this.$on(event, on)
+      }
+
+      this.$off = (event, func) => {
+        if (!func) {
+          this.Event.listeners[event] = []
+          return
+        }
+        remove(this.Event.listeners[event], func)
+      }
+
+      this.$emit = (event, context, inCache) => {
+        this.Event.listeners[event].forEach(func => func(context, inCache))
+      }
+    }
+
+    /**
+     * find nodes which in viewport and trigger load
+     * @return
+     */
+    _lazyLoadHandler () {
+      let catIn = false
+      this.ListenerQueue.forEach((listener, index) => {
+        if (listener.state.loaded) return
+        catIn = listener.checkInView()
+        if (!catIn) return
+        listener.load(() => {
+          if (!listener.error && listener.loaded) {
+            this.ListenerQueue.splice(index, 1)
+          }
+        })
+      })
+    }
+    /**
+    * init IntersectionObserver
+    * set mode to observer
+    * @return
+    */
+    _initIntersectionObserver () {
+      if (!hasIntersectionObserver) return
+      this._observer = new IntersectionObserver(this._observerHandler.bind(this), this.options.observerOptions)
+      if (this.ListenerQueue.length) {
+        this.ListenerQueue.forEach(listener => {
+          this._observer.observe(listener.el)
+        })
+      }
+    }
+
+    /**
+    * init IntersectionObserver
+    * @return
+    */
+    _observerHandler (entries, observer) {
+      entries.forEach(entry => {
+        if (entry.isIntersecting) {
+          this.ListenerQueue.forEach(listener => {
+            if (listener.el === entry.target) {
+              if (listener.state.loaded) return this._observer.unobserve(listener.el)
+              listener.load()
+            }
+          })
+        }
+      })
+    }
+
+    /**
+    * set element attribute with image'url and state
+    * @param  {object} lazyload listener object
+    * @param  {string} state will be rendered
+    * @param  {bool} inCache  is rendered from cache
+    * @return
+    */
+    _elRenderer (listener, state, cache) {
+      if (!listener.el) return
+      const { el, bindType } = listener
+
+      let src
+      switch (state) {
+        case 'loading':
+          src = listener.loading
+          break
+        case 'error':
+          src = listener.error
+          break
+        default:
+          src = listener.src
+          break
+      }
+
+      if (bindType) {
+        el.style[bindType] = 'url("' + src + '")'
+      } else if (el.getAttribute('src') !== src) {
+        el.setAttribute('src', src)
+      }
+
+      el.setAttribute('lazy', state)
+
+      this.$emit(state, listener, cache)
+      this.options.adapter[state] && this.options.adapter[state](listener, this.options)
+
+      if (this.options.dispatchEvent) {
+        const event = new CustomEvent(state, {
+          detail: listener
+        })
+        el.dispatchEvent(event)
+      }
+    }
+
+    /**
+    * generate loading loaded error image url
+    * @param {string} image's src
+    * @return {object} image's loading, loaded, error url
+    */
+    _valueFormatter (value) {
+      let src = value
+      let loading = this.options.loading
+      let error = this.options.error
+
+      // value is object
+      if (isObject(value)) {
+        if (!value.src && !this.options.silent) console.error('Vue Lazyload warning: miss src with ' + value)
+        src = value.src
+        loading = value.loading || this.options.loading
+        error = value.error || this.options.error
+      }
+      return {
+        src,
+        loading,
+        error
+      }
+    }
+  }
+}

node_modules/vue-lazyload/src/listener.js

@@ -0,0 +1,217 @@
+import {
+  loadImageAsync,
+  ObjectKeys,
+  noop
+} from './util'
+
+let imageCache = {}
+
+// el: {
+//     state,
+//     src,
+//     error,
+//     loading
+// }
+
+export default class ReactiveListener {
+  constructor ({ el, src, error, loading, bindType, $parent, options, elRenderer }) {
+    this.el = el
+    this.src = src
+    this.error = error
+    this.loading = loading
+    this.bindType = bindType
+    this.attempt = 0
+
+    this.naturalHeight = 0
+    this.naturalWidth = 0
+
+    this.options = options
+
+    this.rect = null
+
+    this.$parent = $parent
+    this.elRenderer = elRenderer
+
+    this.performanceData = {
+      init: Date.now(),
+      loadStart: 0,
+      loadEnd: 0
+    }
+
+    this.filter()
+    this.initState()
+    this.render('loading', false)
+  }
+
+  /*
+   * init listener state
+   * @return
+   */
+  initState () {
+    this.el.dataset.src = this.src
+    this.state = {
+      error: false,
+      loaded: false,
+      rendered: false
+    }
+  }
+
+  /*
+   * record performance
+   * @return
+   */
+  record (event) {
+    this.performanceData[event] = Date.now()
+  }
+
+  /*
+   * update image listener data
+   * @param  {String} image uri
+   * @param  {String} loading image uri
+   * @param  {String} error image uri
+   * @return
+   */
+  update ({ src, loading, error }) {
+    const oldSrc = this.src
+    this.src = src
+    this.loading = loading
+    this.error = error
+    this.filter()
+    if (oldSrc !== this.src) {
+      this.attempt = 0
+      this.initState()
+    }
+  }
+
+  /*
+   * get el node rect
+   * @return
+   */
+  getRect () {
+    this.rect = this.el.getBoundingClientRect()
+  }
+
+  /*
+   *  check el is in view
+   * @return {Boolean} el is in view
+   */
+  checkInView () {
+    this.getRect()
+    return (this.rect.top < window.innerHeight * this.options.preLoad && this.rect.bottom > this.options.preLoadTop) &&
+            (this.rect.left < window.innerWidth * this.options.preLoad && this.rect.right > 0)
+  }
+
+  /*
+   * listener filter
+   */
+  filter () {
+    ObjectKeys(this.options.filter).map(key => {
+      this.options.filter[key](this, this.options)
+    })
+  }
+
+  /*
+   * render loading first
+   * @params cb:Function
+   * @return
+   */
+  renderLoading (cb) {
+    loadImageAsync({
+      src: this.loading
+    }, data => {
+      this.render('loading', false)
+      cb()
+    }, () => {
+      // handler `loading image` load failed
+      cb()
+      if (!this.options.silent) console.warn(`VueLazyload log: load failed with loading image(${this.loading})`)
+    })
+  }
+
+  /*
+   * try load image and  render it
+   * @return
+   */
+  load (onFinish = noop) {
+    if ((this.attempt > this.options.attempt - 1) && this.state.error) {
+      if (!this.options.silent) console.log(`VueLazyload log: ${this.src} tried too more than ${this.options.attempt} times`)
+      onFinish()
+      return
+    }
+
+    if (this.state.loaded || imageCache[this.src]) {
+      this.state.loaded = true
+      onFinish()
+      return this.render('loaded', true)
+    }
+
+    this.renderLoading(() => {
+      this.attempt++
+
+      this.record('loadStart')
+
+      loadImageAsync({
+        src: this.src
+      }, data => {
+        this.naturalHeight = data.naturalHeight
+        this.naturalWidth = data.naturalWidth
+        this.state.loaded = true
+        this.state.error = false
+        this.record('loadEnd')
+        this.render('loaded', false)
+        imageCache[this.src] = 1
+        onFinish()
+      }, err => {
+        !this.options.silent && console.error(err)
+        this.state.error = true
+        this.state.loaded = false
+        this.render('error', false)
+      })
+    })
+  }
+
+  /*
+   * render image
+   * @param  {String} state to render // ['loading', 'src', 'error']
+   * @param  {String} is form cache
+   * @return
+   */
+  render (state, cache) {
+    this.elRenderer(this, state, cache)
+  }
+
+  /*
+   * output performance data
+   * @return {Object} performance data
+   */
+  performance () {
+    let state = 'loading'
+    let time = 0
+
+    if (this.state.loaded) {
+      state = 'loaded'
+      time = (this.performanceData.loadEnd - this.performanceData.loadStart) / 1000
+    }
+
+    if (this.state.error) state = 'error'
+
+    return {
+      src: this.src,
+      state,
+      time
+    }
+  }
+
+  /*
+   * destroy
+   * @return
+   */
+  destroy () {
+    this.el = null
+    this.src = null
+    this.error = null
+    this.loading = null
+    this.bindType = null
+    this.attempt = 0
+  }
+}

node_modules/vue-lazyload/src/util.js

@@ -0,0 +1,292 @@
+import assign from 'assign-deep'
+
+const inBrowser = typeof window !== 'undefined'
+export const hasIntersectionObserver = inBrowser && 'IntersectionObserver' in window
+
+export const modeType = {
+  event: 'event',
+  observer: 'observer'
+}
+
+// CustomEvent polyfill
+const CustomEvent = (function () {
+  if (!inBrowser) return
+  if (typeof window.CustomEvent === 'function') return window.CustomEvent
+  function CustomEvent (event, params) {
+    params = params || { bubbles: false, cancelable: false, detail: undefined }
+    var evt = document.createEvent('CustomEvent')
+    evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail)
+    return evt
+  }
+  CustomEvent.prototype = window.Event.prototype
+  return CustomEvent
+})()
+
+function remove (arr, item) {
+  if (!arr.length) return
+  const index = arr.indexOf(item)
+  if (index > -1) return arr.splice(index, 1)
+}
+
+function some (arr, fn) {
+  let has = false
+  for (let i = 0, len = arr.length; i < len; i++) {
+    if (fn(arr[i])) {
+      has = true
+      break
+    }
+  }
+  return has
+}
+
+function getBestSelectionFromSrcset (el, scale) {
+  if (el.tagName !== 'IMG' || !el.getAttribute('data-srcset')) return
+
+  let options = el.getAttribute('data-srcset')
+  const result = []
+  const container = el.parentNode
+  const containerWidth = container.offsetWidth * scale
+
+  let spaceIndex
+  let tmpSrc
+  let tmpWidth
+
+  options = options.trim().split(',')
+
+  options.map(item => {
+    item = item.trim()
+    spaceIndex = item.lastIndexOf(' ')
+    if (spaceIndex === -1) {
+      tmpSrc = item
+      tmpWidth = 999998
+    } else {
+      tmpSrc = item.substr(0, spaceIndex)
+      tmpWidth = parseInt(item.substr(spaceIndex + 1, item.length - spaceIndex - 2), 10)
+    }
+    result.push([tmpWidth, tmpSrc])
+  })
+
+  result.sort(function (a, b) {
+    if (a[0] < b[0]) {
+      return -1
+    }
+    if (a[0] > b[0]) {
+      return 1
+    }
+    if (a[0] === b[0]) {
+      if (b[1].indexOf('.webp', b[1].length - 5) !== -1) {
+        return 1
+      }
+      if (a[1].indexOf('.webp', a[1].length - 5) !== -1) {
+        return -1
+      }
+    }
+    return 0
+  })
+  let bestSelectedSrc = ''
+  let tmpOption
+  const resultCount = result.length
+
+  for (let i = 0; i < resultCount; i++) {
+    tmpOption = result[i]
+    if (tmpOption[0] >= containerWidth) {
+      bestSelectedSrc = tmpOption[1]
+      break
+    }
+  }
+
+  return bestSelectedSrc
+}
+
+function find (arr, fn) {
+  let item
+  for (let i = 0, len = arr.length; i < len; i++) {
+    if (fn(arr[i])) {
+      item = arr[i]
+      break
+    }
+  }
+  return item
+}
+
+const getDPR = (scale = 1) => inBrowser ? (window.devicePixelRatio || scale) : scale
+
+function supportWebp () {
+  if (!inBrowser) return false
+
+  let support = true
+  const d = document
+
+  try {
+    let el = d.createElement('object')
+    el.type = 'image/webp'
+    el.style.visibility = 'hidden'
+    el.innerHTML = '!'
+    d.body.appendChild(el)
+    support = !el.offsetWidth
+    d.body.removeChild(el)
+  } catch (err) {
+    support = false
+  }
+
+  return support
+}
+
+function throttle (action, delay) {
+  let timeout = null
+  let lastRun = 0
+  return function () {
+    if (timeout) {
+      return
+    }
+    let elapsed = Date.now() - lastRun
+    let context = this
+    let args = arguments
+    let runCallback = function () {
+      lastRun = Date.now()
+      timeout = false
+      action.apply(context, args)
+    }
+    if (elapsed >= delay) {
+      runCallback()
+    } else {
+      timeout = setTimeout(runCallback, delay)
+    }
+  }
+}
+
+function testSupportsPassive () {
+  if (!inBrowser) return
+  let support = false
+  try {
+    let opts = Object.defineProperty({}, 'passive', {
+      get: function () {
+        support = true
+      }
+    })
+    window.addEventListener('test', null, opts)
+  } catch (e) {}
+  return support
+}
+
+const supportsPassive = testSupportsPassive()
+
+const _ = {
+  on (el, type, func, capture = false) {
+    if (supportsPassive) {
+      el.addEventListener(type, func, {
+        capture: capture,
+        passive: true
+      })
+    } else {
+      el.addEventListener(type, func, capture)
+    }
+  },
+  off (el, type, func, capture = false) {
+    el.removeEventListener(type, func, capture)
+  }
+}
+
+const loadImageAsync = (item, resolve, reject) => {
+  let image = new Image()
+  image.src = item.src
+
+  image.onload = function () {
+    resolve({
+      naturalHeight: image.naturalHeight,
+      naturalWidth: image.naturalWidth,
+      src: image.src
+    })
+  }
+
+  image.onerror = function (e) {
+    reject(e)
+  }
+}
+
+const style = (el, prop) => {
+  return typeof getComputedStyle !== 'undefined'
+    ? getComputedStyle(el, null).getPropertyValue(prop)
+    : el.style[prop]
+}
+
+const overflow = (el) => {
+  return style(el, 'overflow') + style(el, 'overflow-y') + style(el, 'overflow-x')
+}
+
+const scrollParent = (el) => {
+  if (!inBrowser) return
+  if (!(el instanceof HTMLElement)) {
+    return window
+  }
+
+  let parent = el
+
+  while (parent) {
+    if (parent === document.body || parent === document.documentElement) {
+      break
+    }
+
+    if (!parent.parentNode) {
+      break
+    }
+
+    if (/(scroll|auto)/.test(overflow(parent))) {
+      return parent
+    }
+
+    parent = parent.parentNode
+  }
+
+  return window
+}
+
+function isObject (obj) {
+  return obj !== null && typeof obj === 'object'
+}
+
+function ObjectKeys (obj) {
+  if (!(obj instanceof Object)) return []
+  if (Object.keys) {
+    return Object.keys(obj)
+  } else {
+    let keys = []
+    for (let key in obj) {
+      if (obj.hasOwnProperty(key)) {
+        keys.push(key)
+      }
+    }
+    return keys
+  }
+}
+
+function ArrayFrom (arrLike) {
+  let len = arrLike.length
+  const list = []
+  for (let i = 0; i < len; i++) {
+    list.push(arrLike[i])
+  }
+  return list
+}
+
+function noop () {}
+
+export {
+  inBrowser,
+  CustomEvent,
+  remove,
+  some,
+  find,
+  assign,
+  noop,
+  ArrayFrom,
+  _,
+  isObject,
+  throttle,
+  supportWebp,
+  getDPR,
+  scrollParent,
+  loadImageAsync,
+  getBestSelectionFromSrcset,
+  ObjectKeys
+}