index.js

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.forceCheck = exports.lazyload = undefined;

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

var _react = require('react');

var _react2 = _interopRequireDefault(_react);

var _reactDom = require('react-dom');

var _reactDom2 = _interopRequireDefault(_reactDom);

var _event = require('./utils/event');

var _scrollParent = require('./utils/scrollParent');

var _scrollParent2 = _interopRequireDefault(_scrollParent);

var _debounce = require('./utils/debounce');

var _debounce2 = _interopRequireDefault(_debounce);

var _throttle = require('./utils/throttle');

var _throttle2 = _interopRequireDefault(_throttle);

var _propTypes = require('prop-types');

var _propTypes2 = _interopRequireDefault(_propTypes);

var _decorator = require('./decorator');

var _decorator2 = _interopRequireDefault(_decorator);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; } /**
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                * react-lazyload
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                */


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

/**
 * 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 = _reactDom2.default.findDOMNode(component);

  var parentTop = void 0;
  var parentHeight = void 0;

  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 = void 0;
  var height = void 0;

  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 = _reactDom2.default.findDOMNode(component);

  var top = void 0;
  var elementHeight = void 0;

  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 = _reactDom2.default.findDOMNode(component);
  if (!node) {
    return;
  }

  var parent = (0, _scrollParent2.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, yeah I mean `render` call,
    // not actual DOM render
    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
var delayType = void 0;
var finalLazyLoadHandler = null;

var LazyLoad = function (_Component) {
  _inherits(LazyLoad, _Component);

  function LazyLoad(props) {
    _classCallCheck(this, LazyLoad);

    var _this = _possibleConstructorReturn(this, (LazyLoad.__proto__ || Object.getPrototypeOf(LazyLoad)).call(this, props));

    _this.visible = false;
    return _this;
  }

  _createClass(LazyLoad, [{
    key: 'componentDidMount',
    value: function componentDidMount() {
      if (typeof process !== 'undefined' && process.env.NODE_ENV !== 'production') {
        if (_react2.default.Children.count(this.props.children) > 1) {
          console.warn('[react-lazyload] Only one child is allowed to be passed to `LazyLoad`.');
        }

        if (this.props.wheel) {
          // eslint-disable-line
          console.warn('[react-lazyload] Props `wheel` is not supported anymore, try set `overflow` for lazy loading in overflow containers.');
        }

        // Warn the user if placeholder and height is not specified and the rendered height is 0
        if (!this.props.placeholder && this.props.height === undefined && _reactDom2.default.findDOMNode(this).offsetHeight === 0) {
          console.warn('[react-lazyload] Please add `height` props to <LazyLoad> for better performance.');
        }
      }

      // It's unlikely to change delay type on the fly, this is mainly
      // designed for tests
      var needResetFinalLazyLoadHandler = false;
      if (this.props.debounce !== undefined && delayType === 'throttle') {
        console.warn('[react-lazyload] Previous delay function is `throttle`, now switching to `debounce`, try setting them unanimously');
        needResetFinalLazyLoadHandler = true;
      } else if (delayType === 'debounce' && this.props.debounce === undefined) {
        console.warn('[react-lazyload] Previous delay function is `debounce`, now switching to `throttle`, try setting them unanimously');
        needResetFinalLazyLoadHandler = true;
      }

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

      if (!finalLazyLoadHandler) {
        if (this.props.debounce !== undefined) {
          finalLazyLoadHandler = (0, _debounce2.default)(lazyLoadHandler, typeof this.props.debounce === 'number' ? this.props.debounce : 300);
          delayType = 'debounce';
        } else {
          finalLazyLoadHandler = (0, _throttle2.default)(lazyLoadHandler, typeof this.props.throttle === 'number' ? this.props.throttle : 300);
          delayType = 'throttle';
        }
      }

      if (this.props.overflow) {
        var parent = (0, _scrollParent2.default)(_reactDom2.default.findDOMNode(this));
        if (parent && typeof parent.getAttribute === 'function') {
          var listenerCount = 1 + +parent.getAttribute(LISTEN_FLAG);
          if (listenerCount === 1) {
            parent.addEventListener('scroll', finalLazyLoadHandler);
          }
          parent.setAttribute(LISTEN_FLAG, listenerCount);
        }
      } else if (listeners.length === 0 || needResetFinalLazyLoadHandler) {
        var _props = this.props,
            scroll = _props.scroll,
            resize = _props.resize;


        if (scroll) {
          (0, _event.on)(window, 'scroll', finalLazyLoadHandler);
        }

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

      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, _scrollParent2.default)(_reactDom2.default.findDOMNode(this));
        if (parent && typeof parent.getAttribute === 'function') {
          var listenerCount = +parent.getAttribute(LISTEN_FLAG) - 1;
          if (listenerCount === 0) {
            parent.removeEventListener('scroll', finalLazyLoadHandler);
            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) {
        (0, _event.off)(window, 'resize', finalLazyLoadHandler);
        (0, _event.off)(window, 'scroll', finalLazyLoadHandler);
      }
    }
  }, {
    key: 'render',
    value: function render() {
      return this.visible ? this.props.children : this.props.placeholder ? this.props.placeholder : _react2.default.createElement('div', { style: { height: this.props.height }, className: 'lazyload-placeholder' });
    }
  }]);

  return LazyLoad;
}(_react.Component);

LazyLoad.propTypes = {
  once: _propTypes2.default.bool,
  height: _propTypes2.default.oneOfType([_propTypes2.default.number, _propTypes2.default.string]),
  offset: _propTypes2.default.oneOfType([_propTypes2.default.number, _propTypes2.default.arrayOf(_propTypes2.default.number)]),
  overflow: _propTypes2.default.bool,
  resize: _propTypes2.default.bool,
  scroll: _propTypes2.default.bool,
  children: _propTypes2.default.node,
  throttle: _propTypes2.default.oneOfType([_propTypes2.default.number, _propTypes2.default.bool]),
  debounce: _propTypes2.default.oneOfType([_propTypes2.default.number, _propTypes2.default.bool]),
  placeholder: _propTypes2.default.node,
  unmountIfInvisible: _propTypes2.default.bool
};

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

var lazyload = exports.lazyload = _decorator2.default;
exports.default = LazyLoad;
exports.forceCheck = lazyLoadHandler;