v-infinite-scroll 自定义属性

前言:在使用v-infinite-scroll 属性时 发现项目中并没有 此属性   
 
解决：把v-infinite-scroll 源码放在.js文件中导出 使用
 
源码：
 
 
 
const ctx = "@@InfiniteScroll";
 
const throttle = function (fn, delay) {
  let now, lastExec, timer, context, args; //eslint-disable-line
 
  const execute = function () {
    fn.apply(context, args);
    lastExec = now;
  };
 
  return function () {
    context = this;
    args = arguments;
    now = Date.now();
 
    if (timer) {
      clearTimeout(timer);
      timer = null;
    }
 
    if (lastExec) {
      const diff = delay - (now - lastExec);
      if (diff < 0) {
        execute();
      } else {
        timer = setTimeout(() => {
          execute();
        }, diff);
      }
    } else {
      execute();
    }
  };
};
 
const getScrollTop = function (element) {
  if (element === window) {
    return Math.max(window.pageYOffset || 0, document.documentElement.scrollTop);
  }
 
  return element.scrollTop;
};
 
const getComputedStyle = document.defaultView.getComputedStyle;
 
const getScrollEventTarget = function (element) {
  let currentNode = element;
  console.log("drawer:", element);
  // bugfix, see http://w3help.org/zh-cn/causes/SD9013 and http://stackoverflow.com/questions/17016740/onscroll-function-is-not-working-for-chrome
  while (currentNode && currentNode.tagName !== "HTML" && currentNode.tagName !== "BODY" && currentNode.nodeType === 1) {
    const overflowY = getComputedStyle(currentNode).overflowY;
    console.log("drawer:", overflowY);
    const overflowYStyle = currentNode.style.overflowY;
    console.log("drawer:", overflowYStyle);
    if (overflowY === "scroll" || overflowY === "auto" || overflowYStyle === "auto") {
      return currentNode;
    }
    console.log("drawer:", currentNode.parentNode);
    currentNode = currentNode.parentNode;
  }
  return currentNode;
};
 
const getVisibleHeight = function (element) {
  if (element === window) {
    return document.documentElement.clientHeight;
  }
 
  return element.clientHeight;
};
 
const getElementTop = function (element) {
  if (element === window) {
    return getScrollTop(window);
  }
  return element.getBoundingClientRect().top + getScrollTop(window);
};
 
const isAttached = function (element) {
  let currentNode = element.parentNode;
  while (currentNode) {
    if (currentNode.tagName === "HTML") {
      return true;
    }
    if (currentNode.nodeType === 11) {
      return false;
    }
    currentNode = currentNode.parentNode;
  }
  return false;
};
 
const doBind = function () {
  if (this.binded) return; // eslint-disable-line
  this.binded = true;
 
  const directive = this;
  const element = directive.el;
  console.log("directive:", directive, element.parentNode);
  const throttleDelayExpr = element.getAttribute("infinite-scroll-throttle-delay");
  let throttleDelay = 200;
  if (throttleDelayExpr) {
    throttleDelay = Number(directive.vm[throttleDelayExpr] || throttleDelayExpr);
    if (isNaN(throttleDelay) || throttleDelay < 0) {
      throttleDelay = 200;
    }
  }
  directive.throttleDelay = throttleDelay;
 
  directive.scrollEventTarget = getScrollEventTarget(element);
  directive.scrollListener = throttle(doCheck.bind(directive), directive.throttleDelay);
  directive.scrollEventTarget.addEventListener("scroll", directive.scrollListener);
 
  this.vm.$on("hook:beforeDestroy", function () {
    directive.scrollEventTarget.removeEventListener("scroll", directive.scrollListener);
  });
 
  const disabledExpr = element.getAttribute("infinite-scroll-disabled");
  let disabled = false;
  console.log("disabledExpr", disabledExpr);
  if (disabledExpr) {
    this.vm.$watch(disabledExpr, function (value) {
      directive.disabled = value;
      if (!value && directive.immediateCheck) {
        doCheck.call(directive);
      }
    });
    disabled = Boolean(directive.vm[disabledExpr]);
  }
  directive.disabled = disabled;
 
  const distanceExpr = element.getAttribute("infinite-scroll-distance");
  let distance = 0;
  if (distanceExpr) {
    distance = Number(directive.vm[distanceExpr] || distanceExpr);
    if (isNaN(distance)) {
      distance = 0;
    }
  }
  directive.distance = distance;
 
  const immediateCheckExpr = element.getAttribute("infinite-scroll-immediate-check");
  let immediateCheck = true;
  if (immediateCheckExpr) {
    immediateCheck = Boolean(directive.vm[immediateCheckExpr]);
  }
  directive.immediateCheck = immediateCheck;
 
  if (immediateCheck) {
    doCheck.call(directive);
  }
 
  const eventName = element.getAttribute("infinite-scroll-listen-for-event");
  if (eventName) {
    directive.vm.$on(eventName, function () {
      doCheck.call(directive);
    });
  }
};
 
const doCheck = function (force) {
  const scrollEventTarget = this.scrollEventTarget;
  const element = this.el;
  const distance = this.distance;
 
  if (force !== true && this.disabled) return; //eslint-disable-line
  const viewportScrollTop = getScrollTop(scrollEventTarget);
  const viewportBottom = viewportScrollTop + getVisibleHeight(scrollEventTarget);
 
  let shouldTrigger = false;
 
  if (scrollEventTarget === element) {
    shouldTrigger = scrollEventTarget.scrollHeight - viewportBottom <= distance;
  } else {
    const elementBottom = getElementTop(element) - getElementTop(scrollEventTarget) + element.offsetHeight + viewportScrollTop;
 
    shouldTrigger = viewportBottom + distance >= elementBottom;
  }
 
  if (shouldTrigger && this.expression) {
    this.expression();
  }
};
 
export default {
  // bind
  // bind：只调用一次，指令第一次绑定到元素时调用。在这里可以进行一次性的初始化设置。
  // inserted：被绑定元素插入父节点时调用 (仅保证父节点存在，但不一定已被插入文档中)。
  inserted(el, binding, vnode) {
    el[ctx] = {
      el,
      vm: vnode.context,
      expression: binding.value,
    };
    const args = arguments;
 
    doBind.call(el[ctx]);
    el[ctx].vm.$nextTick().then(function () {
      if (isAttached(el)) {
        doBind.call(el[ctx], args);
      }
 
      el[ctx].bindTryCount = 0;
 
      const tryBind = function () {
        if (el[ctx].bindTryCount > 10) return; //eslint-disable-line
        el[ctx].bindTryCount++;
        if (isAttached(el)) {
          doBind.call(el[ctx], args);
        } else {
          setTimeout(tryBind, 50);
        }
      };
      tryBind();
    });
  },
 
  unbind(el) {
    if (el && el[ctx] && el[ctx].scrollEventTarget) {
      el[ctx].scrollEventTarget.removeEventListener("scroll", el[ctx].scrollListener);
    }
  },
};
 
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 v-infinite-scroll="onLazyLoad"   使用方法添加事件函数
 
onLazyLoad(){
....................
}