tntd/es/scroll-bar/Thumb.js

tntd是基于 TNT Design 设计体系的 React UI 组件库，主要用于研发企业级中后台产品。

"use strict";

function _typeof(o) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (o) { return typeof o; } : function (o) { return o && "function" == typeof Symbol && o.constructor === Symbol && o !== Symbol.prototype ? "symbol" : typeof o; }, _typeof(o); }
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = Thumb;
var _classnames = _interopRequireDefault(require("classnames"));
var _react = _interopRequireWildcard(require("react"));
var _Context = _interopRequireDefault(require("./Context"));
var _util = require("./util");
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" != _typeof(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; }
function _interopRequireDefault(e) { return e && e.__esModule ? e : { "default": e }; }
function _slicedToArray(r, e) { return _arrayWithHoles(r) || _iterableToArrayLimit(r, e) || _unsupportedIterableToArray(r, e) || _nonIterableRest(); }
function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }
function _unsupportedIterableToArray(r, a) { if (r) { if ("string" == typeof r) return _arrayLikeToArray(r, a); var t = {}.toString.call(r).slice(8, -1); return "Object" === t && r.constructor && (t = r.constructor.name), "Map" === t || "Set" === t ? Array.from(r) : "Arguments" === t || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(t) ? _arrayLikeToArray(r, a) : void 0; } }
function _arrayLikeToArray(r, a) { (null == a || a > r.length) && (a = r.length); for (var e = 0, n = Array(a); e < a; e++) n[e] = r[e]; return n; }
function _iterableToArrayLimit(r, l) { var t = null == r ? null : "undefined" != typeof Symbol && r[Symbol.iterator] || r["@@iterator"]; if (null != t) { var e, n, i, u, a = [], f = !0, o = !1; try { if (i = (t = t.call(r)).next, 0 === l) { if (Object(t) !== t) return; f = !1; } else for (; !(f = (e = i.call(t)).done) && (a.push(e.value), a.length !== l); f = !0); } catch (r) { o = !0, n = r; } finally { try { if (!f && null != t["return"] && (u = t["return"](), Object(u) !== u)) return; } finally { if (o) throw n; } } return a; } }
function _arrayWithHoles(r) { if (Array.isArray(r)) return r; }
function Thumb(props) {
  var _useContext = (0, _react.useContext)(_Context["default"]),
    scrollbarElement = _useContext.scrollbarElement,
    wrapElement = _useContext.wrapElement;
  var instance = (0, _react.useRef)();
  var thumb = (0, _react.useRef)();
  var _useState = (0, _react.useState)(false),
    _useState2 = _slicedToArray(_useState, 2),
    visible = _useState2[0],
    setVisible = _useState2[1];
  // 当作非响应式变量使用
  var thumbState = (0, _react.useRef)({});
  var cursorDown = (0, _react.useRef)(false);
  var cursorLeave = (0, _react.useRef)(false);
  var originalOnSelectStart = (0, _react.useRef)(document.onselectstart);
  var bar = _util.BAR_MAP[props.vertical ? 'vertical' : 'horizontal'];
  (0, _react.useEffect)(function () {
    var element = scrollbarElement.current;
    element.addEventListener('mousemove', mouseMoveScrollbarHandler);
    element.addEventListener('mouseleave', mouseLeaveScrollbarHandler);
    return function () {
      restoreOnselectstart();
      document.removeEventListener('mouseup', mouseUpDocumentHandler);
      element.removeEventListener('mousemove', mouseMoveScrollbarHandler);
      element.removeEventListener('mouseleave', mouseLeaveScrollbarHandler);
    };
  }, []);
  function mouseMoveScrollbarHandler() {
    cursorLeave.current = false;
    setVisible(true);
  }
  function mouseLeaveScrollbarHandler() {
    cursorLeave.current = true;
    setVisible(cursorDown.current);
  }
  function getOffsetRatio() {
    return Math.pow(instance.current[bar.offset], 2) / wrapElement.current[bar.scrollSize] / props.ratio / thumb.current[bar.offset];
  }
  function clickTrackHandler(e) {
    if (!thumb.current || !instance.current || !wrapElement.current) return;
    // 鼠标点击的坐标距离顶端的距离
    var offset = Math.abs(e.target.getBoundingClientRect()[bar.direction] - e[bar.client]);
    var thumbHalf = thumb.current[bar.offset] / 2;
    var thumbPositionPercentage = (offset - thumbHalf) * 100 * getOffsetRatio() / instance.current[bar.offset];
    // 直接给scrollTop赋值，就会调用bar组件的handleScroll函数
    wrapElement.current[bar.scroll] = thumbPositionPercentage * wrapElement.current[bar.scrollSize] / 100;
  }
  function clickThumbHandler(e) {
    var _a;
    e.stopPropagation();
    if (e.ctrlKey || [1, 2].includes(e.button)) return;
    (_a = window.getSelection()) === null || _a === void 0 ? void 0 : _a.removeAllRanges();
    startDrag(e);
    var el = e.currentTarget;
    if (!el) return;
    thumbState.current[bar.axis] = el[bar.offset] - (e[bar.client] - el.getBoundingClientRect()[bar.direction]);
  }
  function startDrag(e) {
    e.persist();
    cursorDown.current = true;
    document.addEventListener('mousemove', mouseMoveDocumentHandler);
    document.addEventListener('mouseup', mouseUpDocumentHandler);
    originalOnSelectStart.current = document.onselectstart;
    document.onselectstart = function () {
      return false;
    };
  }
  function mouseMoveDocumentHandler(e) {
    if (!instance.current || !thumb.current) return;
    if (cursorDown.current === false) return;
    var prevPage = thumbState.current[bar.axis];
    if (!prevPage) return;
    var offset = (instance.current.getBoundingClientRect()[bar.direction] - e[bar.client]) * -1;
    var thumbClickPosition = thumb.current[bar.offset] - prevPage;
    var thumbPositionPercentage = (offset - thumbClickPosition) * 100 * getOffsetRatio() / instance.current[bar.offset];
    wrapElement.current[bar.scroll] = thumbPositionPercentage * wrapElement.current[bar.scrollSize] / 100;
  }
  function mouseUpDocumentHandler() {
    cursorDown.current = false;
    thumbState.current[bar.axis] = 0;
    document.removeEventListener('mousemove', mouseMoveDocumentHandler);
    document.removeEventListener('mouseup', mouseUpDocumentHandler);
    restoreOnselectstart();
    if (cursorLeave.current) setVisible(false);
  }
  function restoreOnselectstart() {
    if (document.onselectstart !== originalOnSelectStart.current) document.onselectstart = originalOnSelectStart.current;
  }
  var thumbStyle = (0, _util.renderThumbStyle)({
    size: props.size,
    move: props.move,
    bar: bar
  });
  return _react["default"].createElement("div", {
    hidden: !(props.always || visible),
    className: (0, _classnames["default"])('tntd-scroll-bar-bar', bar.key),
    ref: instance,
    onMouseDown: clickTrackHandler
  }, _react["default"].createElement("div", {
    className: "tntd-scroll-bar-thumb",
    style: thumbStyle,
    ref: thumb,
    onMouseDown: clickThumbHandler
  }));
}