@jdcfe/yep-react/lib/lazy-load/index.js

一套移动端的React组件库

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _typeof = require("@babel/runtime/helpers/typeof");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.forceCheck = exports.default = void 0;

var _classCallCheck2 = _interopRequireDefault(require("@babel/runtime/helpers/classCallCheck"));

var _createClass2 = _interopRequireDefault(require("@babel/runtime/helpers/createClass"));

var _inherits2 = _interopRequireDefault(require("@babel/runtime/helpers/inherits"));

var _possibleConstructorReturn2 = _interopRequireDefault(require("@babel/runtime/helpers/possibleConstructorReturn"));

var _getPrototypeOf2 = _interopRequireDefault(require("@babel/runtime/helpers/getPrototypeOf"));

var React = _interopRequireWildcard(require("react"));

var ReactDom = _interopRequireWildcard(require("react-dom"));

var _events = require("../_utils/events");

var _scrollParent = _interopRequireDefault(require("../_utils/scrollParent"));

var _throttle = _interopRequireDefault(require("lodash/throttle"));

var _debounce = _interopRequireDefault(require("lodash/debounce"));

function _getRequireWildcardCache(nodeInterop) { if (typeof WeakMap !== "function") return null; var cacheBabelInterop = new WeakMap(); var cacheNodeInterop = new WeakMap(); return (_getRequireWildcardCache = function _getRequireWildcardCache(nodeInterop) { return nodeInterop ? cacheNodeInterop : cacheBabelInterop; })(nodeInterop); }

function _interopRequireWildcard(obj, nodeInterop) { if (!nodeInterop && obj && obj.__esModule) { return obj; } if (obj === null || _typeof(obj) !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(nodeInterop); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (key !== "default" && Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }

function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = (0, _getPrototypeOf2.default)(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = (0, _getPrototypeOf2.default)(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return (0, _possibleConstructorReturn2.default)(this, result); }; }

function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Boolean.prototype.valueOf.call(Reflect.construct(Boolean, [], function () {})); return true; } catch (e) { return false; } }

var defaultBoundingClientRect = {
  top: 0,
  right: 0,
  bottom: 0,
  left: 0,
  width: 0,
  height: 0
};
var LISTEN_FLAG = 'data-lazyload-listened';
var listeners = [];
var pending = []; // try to handle passive events

var passiveEventSupported = false;

try {
  var opts = Object.defineProperty({}, 'passive', {
    get: function get() {
      passiveEventSupported = true;
    }
  });
  window.addEventListener('test', function () {}, opts);
} catch (e) {} // if they are supported, setup the optional params
// IMPORTANT: FALSE doubles as the default CAPTURE value!


var passiveEvent = passiveEventSupported ? {
  capture: false,
  passive: true
} : false;
/**
 * Check if `component` is visible in overflow container `parent`
 * @param  {node} component React component
 * @param  {node} parent    component's scroll parent
 * @return {bool}
 */

var checkOverflowVisible = function checkOverflowVisible(component, parent) {
  var node = ReactDom.findDOMNode(component);
  var parentTop;
  var parentHeight;

  try {
    var _parent$getBoundingCl = parent.getBoundingClientRect();

    parentTop = _parent$getBoundingCl.top;
    parentHeight = _parent$getBoundingCl.height;
  } catch (e) {
    parentTop = defaultBoundingClientRect.top;
    parentHeight = defaultBoundingClientRect.height;
  }

  var windowInnerHeight = window.innerHeight || document.documentElement.clientHeight; // calculate top and height of the intersection of the element's scrollParent and viewport

  var intersectionTop = Math.max(parentTop, 0); // intersection's top relative to viewport

  var intersectionHeight = Math.min(windowInnerHeight, parentTop + parentHeight) - intersectionTop; // height
  // check whether the element is visible in the intersection

  var top;
  var height;

  try {
    var _node$getBoundingClie = node.getBoundingClientRect();

    top = _node$getBoundingClie.top;
    height = _node$getBoundingClie.height;
  } catch (e) {
    top = defaultBoundingClientRect.top;
    height = defaultBoundingClientRect.height;
  }

  var offsetTop = top - intersectionTop; // element's top relative to intersection

  var offsets = Array.isArray(component.props.offset) ? component.props.offset : [component.props.offset, component.props.offset]; // Be compatible with previous API

  return offsetTop - offsets[0] <= intersectionHeight && offsetTop + height + offsets[1] >= 0;
};
/**
 * Check if `component` is visible in document
 * @param  {node} component React component
 * @return {bool}
 */


var checkNormalVisible = function checkNormalVisible(component) {
  var node = ReactDom.findDOMNode(component); // If this element is hidden by css rules somehow, it's definitely invisible

  if (!(node.offsetWidth || node.offsetHeight || node.getClientRects().length)) return false;
  var top;
  var elementHeight;

  try {
    var _node$getBoundingClie2 = node.getBoundingClientRect();

    top = _node$getBoundingClie2.top;
    elementHeight = _node$getBoundingClie2.height;
  } catch (e) {
    top = defaultBoundingClientRect.top;
    elementHeight = defaultBoundingClientRect.height;
  }

  var windowInnerHeight = window.innerHeight || document.documentElement.clientHeight;
  var offsets = Array.isArray(component.props.offset) ? component.props.offset : [component.props.offset, component.props.offset]; // Be compatible with previous API

  return top - offsets[0] <= windowInnerHeight && top + elementHeight + offsets[1] >= 0;
};
/**
 * Detect if element is visible in viewport, if so, set `visible` state to true.
 * If `once` prop is provided true, remove component as listener after checkVisible
 *
 * @param  {React} component   React component that respond to scroll and resize
 */


var checkVisible = function checkVisible(component) {
  var node = ReactDom.findDOMNode(component);

  if (!(node instanceof HTMLElement)) {
    return;
  }

  var parent = (0, _scrollParent.default)(node);
  var isOverflow = component.props.overflow && parent !== node.ownerDocument && parent !== document && parent !== document.documentElement;
  var visible = isOverflow ? checkOverflowVisible(component, parent) : checkNormalVisible(component);

  if (visible) {
    // Avoid extra render if previously is visible
    if (!component.visible) {
      if (component.props.once) {
        pending.push(component);
      }

      component.visible = true;
      component.forceUpdate();
    }
  } else if (!(component.props.once && component.visible)) {
    component.visible = false;

    if (component.props.unmountIfInvisible) {
      component.forceUpdate();
    }
  }
};

var purgePending = function purgePending() {
  pending.forEach(function (component) {
    var index = listeners.indexOf(component);

    if (index !== -1) {
      listeners.splice(index, 1);
    }
  });
  pending = [];
};

var lazyLoadHandler = function lazyLoadHandler() {
  for (var i = 0; i < listeners.length; ++i) {
    var listener = listeners[i];
    checkVisible(listener);
  } // Remove `once` component in listeners


  purgePending();
}; // Depending on component's props


exports.forceCheck = lazyLoadHandler;
var delayType;
var finalLazyLoadHandler = null;

var isString = function isString(str) {
  return typeof str === 'string';
};

var LazyLoad = /*#__PURE__*/function (_React$Component) {
  (0, _inherits2.default)(LazyLoad, _React$Component);

  var _super = _createSuper(LazyLoad);

  function LazyLoad(props) {
    var _this;

    (0, _classCallCheck2.default)(this, LazyLoad);
    _this = _super.call(this, props);
    _this.visible = false;
    return _this;
  }

  (0, _createClass2.default)(LazyLoad, [{
    key: "componentDidMount",
    value: function componentDidMount() {
      // It's unlikely to change delay type on the fly, this is mainly
      // designed for tests
      var scrollport = window;
      var scrollContainer = this.props.scrollContainer;

      if (scrollContainer) {
        if (isString(scrollContainer)) {
          scrollport = scrollport.document.querySelector(scrollContainer);
        }
      }

      var needResetFinalLazyLoadHandler = this.props.debounce !== undefined && delayType === 'throttle' || delayType === 'debounce' && this.props.debounce === undefined;

      if (needResetFinalLazyLoadHandler) {
        (0, _events.off)(scrollport, 'scroll', finalLazyLoadHandler, passiveEvent);
        (0, _events.off)(window, 'resize', finalLazyLoadHandler, passiveEvent);
        finalLazyLoadHandler = null;
      }

      if (!finalLazyLoadHandler) {
        if (this.props.debounce !== undefined) {
          finalLazyLoadHandler = (0, _debounce.default)(lazyLoadHandler, typeof this.props.debounce === 'number' ? this.props.debounce : 300);
          delayType = 'debounce';
        } else if (this.props.throttle !== undefined) {
          finalLazyLoadHandler = (0, _throttle.default)(lazyLoadHandler, typeof this.props.throttle === 'number' ? this.props.throttle : 300);
          delayType = 'throttle';
        } else {
          finalLazyLoadHandler = lazyLoadHandler;
        }
      }

      if (this.props.overflow) {
        var parent = (0, _scrollParent.default)(ReactDom.findDOMNode(this));

        if (parent && typeof parent.getAttribute === 'function') {
          var listenerCount = 1 + +parent.getAttribute(LISTEN_FLAG);

          if (listenerCount === 1) {
            parent.addEventListener('scroll', finalLazyLoadHandler, passiveEvent);
          }

          parent.setAttribute(LISTEN_FLAG, listenerCount);
        }
      } else if (listeners.length === 0 || needResetFinalLazyLoadHandler) {
        var _this$props = this.props,
            scroll = _this$props.scroll,
            resize = _this$props.resize;

        if (scroll) {
          (0, _events.on)(scrollport, 'scroll', finalLazyLoadHandler, passiveEvent);
        }

        if (resize) {
          (0, _events.on)(window, 'resize', finalLazyLoadHandler, passiveEvent);
        }
      }

      listeners.push(this);
      checkVisible(this);
    }
  }, {
    key: "shouldComponentUpdate",
    value: function shouldComponentUpdate() {
      return this.visible;
    }
  }, {
    key: "componentWillUnmount",
    value: function componentWillUnmount() {
      if (this.props.overflow) {
        var parent = (0, _scrollParent.default)(ReactDom.findDOMNode(this));

        if (parent && typeof parent.getAttribute === 'function') {
          var listenerCount = +parent.getAttribute(LISTEN_FLAG) - 1;

          if (listenerCount === 0) {
            parent.removeEventListener('scroll', finalLazyLoadHandler, passiveEvent);
            parent.removeAttribute(LISTEN_FLAG);
          } else {
            parent.setAttribute(LISTEN_FLAG, listenerCount);
          }
        }
      }

      var index = listeners.indexOf(this);

      if (index !== -1) {
        listeners.splice(index, 1);
      }

      if (listeners.length === 0 && typeof window !== 'undefined') {
        (0, _events.off)(window, 'resize', finalLazyLoadHandler, passiveEvent);
        (0, _events.off)(window, 'scroll', finalLazyLoadHandler, passiveEvent);
      }
    }
  }, {
    key: "render",
    value: function render() {
      return this.visible ? this.props.children : this.props.placeholder ? this.props.placeholder : /*#__PURE__*/React.createElement("div", {
        style: {
          height: this.props.height
        },
        className: "lazyload-placeholder"
      });
    }
  }]);
  return LazyLoad;
}(React.Component);

LazyLoad.defaultProps = {
  once: false,
  offset: 0,
  overflow: false,
  resize: false,
  scroll: true,
  unmountIfInvisible: false
};

var getDisplayName = function getDisplayName(WrappedComponent) {
  return WrappedComponent.displayName || WrappedComponent.name || 'Component';
};

var decorator = function decorator(options) {
  return function lazyload(WrappedComponent) {
    return /*#__PURE__*/function (_React$Component2) {
      (0, _inherits2.default)(LazyLoadDecorated, _React$Component2);

      var _super2 = _createSuper(LazyLoadDecorated);

      function LazyLoadDecorated() {
        var _this2;

        (0, _classCallCheck2.default)(this, LazyLoadDecorated);
        _this2 = _super2.apply(this, arguments);
        _this2.displayName = "LazyLoad".concat(getDisplayName(WrappedComponent));
        return _this2;
      }

      (0, _createClass2.default)(LazyLoadDecorated, [{
        key: "render",
        value: function render() {
          return /*#__PURE__*/React.createElement(LazyLoad, options, /*#__PURE__*/React.createElement(WrappedComponent, this.props));
        }
      }]);
      return LazyLoadDecorated;
    }(React.Component);
  };
};

LazyLoad.lazyload = decorator;
var _default = LazyLoad;
exports.default = _default;