213 lines
8.6 KiB
JavaScript
213 lines
8.6 KiB
JavaScript
'use strict';
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };
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exports["default"] = bigData;
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var _react = require('react');
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var _react2 = _interopRequireDefault(_react);
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var _propTypes = require('prop-types');
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var _propTypes2 = _interopRequireDefault(_propTypes);
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }
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function _defaults(obj, defaults) { var keys = Object.getOwnPropertyNames(defaults); for (var i = 0; i < keys.length; i++) { var key = keys[i]; var value = Object.getOwnPropertyDescriptor(defaults, key); if (value && value.configurable && obj[key] === undefined) { Object.defineProperty(obj, key, value); } } return obj; }
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function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
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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; }
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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) : _defaults(subClass, superClass); }
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var defaultHeight = 40;
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var rowDiff = 3; //行差值
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function bigData(Table) {
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var _class, _temp, _initialiseProps;
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return _temp = _class = function (_Component) {
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_inherits(BigData, _Component);
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function BigData(props) {
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_classCallCheck(this, BigData);
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var _this2 = _possibleConstructorReturn(this, _Component.call(this, props));
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_initialiseProps.call(_this2);
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_this2.state = {
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scrollLeft: 0,
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scrollTop: 0
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};
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var rowHeight = _this2.props.height ? _this2.props.height : defaultHeight;
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//默认显示25条，rowsInView根据定高算的。在非固定高下，这个只是一个大概的值。
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_this2.rowsInView = _this2.props.scroll.y ? Math.ceil(_this2.props.scroll.y / rowHeight) : 20;
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_this2.currentIndex = 0;
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_this2.loadCount = props.loadBuffer ? _this2.rowsInView + props.loadBuffer * 2 : 26; //一次加载多少数据
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_this2.cachedRowHeight = []; //缓存每行的高度
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_this2.lastScrollTop = 0;
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_this2.currentScrollTop = 0;
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_this2.startIndex = _this2.currentIndex; //数据开始位置
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_this2.endIndex = _this2.currentIndex + _this2.loadCount; //数据结束位置
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_this2.setRowHeight = _this2.setRowHeight.bind(_this2);
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return _this2;
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}
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/**
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*获取数据区高度
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*
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*
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**/
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BigData.prototype.getContentHeight = function getContentHeight() {
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if (!this.props.data) return 0;
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return this.getSumHeight(0, this.props.data.length);
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};
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BigData.prototype.getSumHeight = function getSumHeight(start, end) {
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var height = this.props.height;
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var rowHeight = height ? height : defaultHeight;
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var sumHeight = 0;
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for (var i = start; i < end; i++) {
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sumHeight += this.cachedRowHeight[i] || rowHeight;
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}
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return sumHeight;
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};
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/**
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*@description 根据返回的scrollTop计算当前的索引。此处做了两次缓存一个是根据上一次的currentIndex计算当前currentIndex。另一个是根据当前内容区的数据是否在缓存中如果在则不重新render页面
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*@param 最新一次滚动的scrollTop
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*/
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BigData.prototype.setRowHeight = function setRowHeight(height, index) {
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this.cachedRowHeight[index] = height;
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};
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BigData.prototype.render = function render() {
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var data = this.props.data;
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var scrollTop = this.scrollTop;
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var endIndex = this.endIndex,
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startIndex = this.startIndex;
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var lazyLoad = {
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preHeight: this.getSumHeight(0, startIndex),
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sufHeight: this.getSumHeight(endIndex, data.length),
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startIndex: startIndex
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};
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return _react2["default"].createElement(Table, _extends({}, this.props, {
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data: data.slice(startIndex, endIndex),
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lazyLoad: lazyLoad,
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handleScroll: this.handleScroll,
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scrollTop: scrollTop,
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setRowHeight: this.setRowHeight
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// className={'lazy-table'}
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}));
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};
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return BigData;
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}(_react.Component), _class.defaultProps = {
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data: [],
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loadBuffer: 5
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}, _class.propTypes = {
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loadBuffer: _propTypes2["default"].number
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}, _initialiseProps = function _initialiseProps() {
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var _this3 = this;
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this.handleScroll = function (nextScrollTop) {
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var _this = _this3;
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var _this$props = _this.props,
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data = _this$props.data,
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height = _this$props.height,
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_this$props$scroll = _this$props.scroll,
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scroll = _this$props$scroll === undefined ? {} : _this$props$scroll;
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var rowHeight = height ? height : defaultHeight;
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var _this$currentIndex = _this.currentIndex,
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currentIndex = _this$currentIndex === undefined ? 0 : _this$currentIndex,
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loadCount = _this.loadCount,
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scrollTop = _this.scrollTop,
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currentScrollTop = _this.currentScrollTop;
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var endIndex = _this.endIndex,
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startIndex = _this.startIndex;
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var needRender = _this.state.needRender;
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var index = currentIndex; //记录下次当前位置
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var temp = currentIndex ? nextScrollTop - currentScrollTop : nextScrollTop;
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var viewHeight = parseInt(scroll.y);
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var isOrder = temp > 0 ? true : false; //true为向下滚动、false为向上滚动
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//根据scrollTop计算下次当前索引的位置
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if (isOrder) {
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while (temp > 0) {
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temp -= _this3.cachedRowHeight[index] || rowHeight;
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if (temp > 0) {
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index += 1;
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//保存当前index对应的scrollTop
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_this3.currentScrollTop += _this3.cachedRowHeight[index] || rowHeight;
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}
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}
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} else {
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while (temp < 0) {
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temp += _this3.cachedRowHeight[index] || rowHeight;
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if (temp < 0) {
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index -= 1;
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_this3.currentScrollTop -= _this3.cachedRowHeight[index] || rowHeight;
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}
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}
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}
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if (index < 0) index = 0;
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console.log('currentIndex****' + index);
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//如果之前的索引和下一次的不一样则重置索引和滚动的位置
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if (currentIndex !== index) {
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_this.currentIndex = index;
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_this.scrollTop = nextScrollTop;
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var rowsInView = 0; //可视区域显示多少行
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var rowsHeight = 0; //可视区域内容高度
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//如果可视区域中需要展示的数据已经在缓存中则不重现render。
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if (viewHeight) {
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//有时滚动过快时this.cachedRowHeight[rowsInView + index]为undifined
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while (rowsHeight < viewHeight && _this3.cachedRowHeight[rowsInView + index]) {
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rowsHeight += _this3.cachedRowHeight[rowsInView + index];
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rowsInView++;
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}
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// 如果rowsInView 小于 缓存的数据则重新render
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// 向下滚动 下临界值超出缓存的endIndex则重新渲染
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if (rowsInView + index > endIndex - rowDiff && isOrder) {
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_this3.startIndex = index;
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endIndex = _this3.startIndex + loadCount;
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if (endIndex > data.length) {
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endIndex = data.length;
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}
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_this3.endIndex = endIndex;
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_this3.setState({ needRender: !needRender });
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}
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// 向上滚动，当前的index是否已经加载（currentIndex），若干上临界值小于startIndex则重新渲染
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if (!isOrder && index < startIndex + rowDiff) {
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startIndex = index - _this3.loadCount / 2;
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if (startIndex < 0) {
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startIndex = 0;
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}
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_this3.startIndex = startIndex;
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_this3.endIndex = _this3.startIndex + loadCount;
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_this3.setState({ needRender: !needRender });
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}
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}
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console.log('**index**' + index, "**startIndex**" + _this3.startIndex, "**endIndex**" + _this3.endIndex);
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}
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};
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}, _temp;
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}
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module.exports = exports['default']; |