@ucloud-pccl/react-components/lib/hooks/useSimpleVirtualList.js

UCloud pccl react components

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
var _typeof3 = require("@babel/runtime/helpers/typeof");
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.useSimpleVirtualList = exports.default = void 0;
var _slicedToArray2 = _interopRequireDefault(require("@babel/runtime/helpers/slicedToArray"));
var _typeof2 = _interopRequireDefault(require("@babel/runtime/helpers/typeof"));
var _newArrowCheck2 = _interopRequireDefault(require("@babel/runtime/helpers/newArrowCheck"));
var _react = _interopRequireWildcard(require("react"));
var _this = void 0;
function _getRequireWildcardCache(e) { if ("function" != typeof WeakMap) return null; var r = new WeakMap(), t = new WeakMap(); return (_getRequireWildcardCache = function _getRequireWildcardCache(e) { return e ? t : r; })(e); }
function _interopRequireWildcard(e, r) { if (!r && e && e.__esModule) return e; if (null === e || "object" != _typeof3(e) && "function" != typeof e) return { default: e }; var t = _getRequireWildcardCache(r); if (t && t.has(e)) return t.get(e); var n = { __proto__: null }, a = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var u in e) if ("default" !== u && {}.hasOwnProperty.call(e, u)) { var i = a ? Object.getOwnPropertyDescriptor(e, u) : null; i && (i.get || i.set) ? Object.defineProperty(n, u, i) : n[u] = e[u]; } return n.default = e, t && t.set(e, n), n; }
var CLIENT_HEIGHT = function CLIENT_HEIGHT() {
  (0, _newArrowCheck2.default)(this, _this);
  return (typeof window === "undefined" ? "undefined" : (0, _typeof2.default)(window)) !== undefined ? window.innerHeight : 1080;
}.bind(void 0);
var FAIL_OFFSET = 2;
var useSimpleVirtualList = exports.useSimpleVirtualList = function useSimpleVirtualList(scrollerRef, wrapperRef, heightWrapperRef, children) {
  var _this2 = this;
  var _ref = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : {},
    _ref$clientHeight = _ref.clientHeight,
    clientHeight = _ref$clientHeight === void 0 ? CLIENT_HEIGHT() : _ref$clientHeight,
    _ref$itemHeight = _ref.itemHeight,
    itemHeight = _ref$itemHeight === void 0 ? 20 : _ref$itemHeight;
  var _useState = (0, _react.useState)(0),
    _useState2 = (0, _slicedToArray2.default)(_useState, 2),
    scrollTop = _useState2[0],
    setScrollTop = _useState2[1];
  var _useState3 = (0, _react.useState)(itemHeight),
    _useState4 = (0, _slicedToArray2.default)(_useState3, 2),
    measuredItemHeight = _useState4[0],
    setMeasuredItemHeight = _useState4[1];
  var _useState5 = (0, _react.useState)(clientHeight),
    _useState6 = (0, _slicedToArray2.default)(_useState5, 2),
    measuredClientHeight = _useState6[0],
    setMeasuredClientHeight = _useState6[1];

  // visible count of children
  var visibleCount = (0, _react.useMemo)(function () {
    (0, _newArrowCheck2.default)(this, _this2);
    return (measuredClientHeight / measuredItemHeight | 0) + FAIL_OFFSET * 2;
  }.bind(this), [measuredClientHeight, measuredItemHeight]);

  // measure when first mount
  (0, _react.useEffect)(function () {
    (0, _newArrowCheck2.default)(this, _this2);
    var scroller = scrollerRef.current;
    var wrapper = wrapperRef.current;
    var heightWrapper = heightWrapperRef.current;
    if (!scroller || !wrapper || !heightWrapper) {
      console.error('scroller, wrapper, heightWrapper is invalid');
      return;
    }
    var firstItem = wrapper.children[0];
    if (!firstItem) {
      console.error('First item is invalid');
      return;
    }
    var itemRect = firstItem.getBoundingClientRect();
    // full height of all items
    var fullHeight = itemRect.height * children.length;
    // set height after current items measured
    heightWrapper.style.height = fullHeight + 'px';
    var scrollRect = scroller.getBoundingClientRect();
    setScrollTop(scroller.scrollTop);
    setMeasuredItemHeight(itemRect.height);
    setMeasuredClientHeight(scrollRect.height);
  }.bind(this), [children.length, heightWrapperRef, scrollerRef, wrapperRef]);

  // offset from first visible child
  var offset = (0, _react.useMemo)(function () {
    (0, _newArrowCheck2.default)(this, _this2);
    return Math.min(Math.max((scrollTop / measuredItemHeight | 0) - FAIL_OFFSET, 0), Math.max(children.length - visibleCount, 0));
  }.bind(this), [children.length, measuredItemHeight, scrollTop, visibleCount]);

  // listen onscroll
  (0, _react.useEffect)(function () {
    var _this3 = this;
    (0, _newArrowCheck2.default)(this, _this2);
    var scroller = scrollerRef.current;
    var onScroll = function onScroll(e) {
      (0, _newArrowCheck2.default)(this, _this3);
      if (!scroller) return;
      if (e.currentTarget !== scroller) return;
      setScrollTop(scroller.scrollTop);
    }.bind(this);
    if (scroller) {
      // initial scrollTop
      setScrollTop(scroller.scrollTop);
      scroller.addEventListener('scroll', onScroll);
    }
    return function () {
      (0, _newArrowCheck2.default)(this, _this3);
      if (scroller) scroller.removeEventListener('scroll', onScroll);
    }.bind(this);
  }.bind(this), [scrollerRef]);

  // children should render
  var renderChildren = (0, _react.useMemo)(function () {
    (0, _newArrowCheck2.default)(this, _this2);
    return children.slice(offset, visibleCount + offset);
  }.bind(this), [children, offset, visibleCount]);

  // offset height from top
  var offsetTop = (0, _react.useMemo)(function () {
    (0, _newArrowCheck2.default)(this, _this2);
    return offset * measuredItemHeight;
  }.bind(this), [measuredItemHeight, offset]);
  return [renderChildren, offsetTop];
};
var _default = exports.default = useSimpleVirtualList;