@rc-component/tabs/lib/hooks/useVisibleRange.js

tabs ui component for react

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = useVisibleRange;
var _react = require("react");
const DEFAULT_SIZE = {
  width: 0,
  height: 0,
  left: 0,
  top: 0,
  right: 0
};
function useVisibleRange(tabOffsets, visibleTabContentValue, transform, tabContentSizeValue, addNodeSizeValue, operationNodeSizeValue, {
  tabs,
  tabPosition,
  rtl
}) {
  let charUnit;
  let position;
  let transformSize;
  if (['top', 'bottom'].includes(tabPosition)) {
    charUnit = 'width';
    position = rtl ? 'right' : 'left';
    transformSize = Math.abs(transform);
  } else {
    charUnit = 'height';
    position = 'top';
    transformSize = -transform;
  }
  return (0, _react.useMemo)(() => {
    if (!tabs.length) {
      return [0, 0];
    }
    const len = tabs.length;
    let endIndex = len;
    for (let i = 0; i < len; i += 1) {
      const offset = tabOffsets.get(tabs[i].key) || DEFAULT_SIZE;
      if (Math.floor(offset[position] + offset[charUnit]) > Math.floor(transformSize + visibleTabContentValue)) {
        endIndex = i - 1;
        break;
      }
    }
    let startIndex = 0;
    for (let i = len - 1; i >= 0; i -= 1) {
      const offset = tabOffsets.get(tabs[i].key) || DEFAULT_SIZE;
      if (offset[position] < transformSize) {
        startIndex = i + 1;
        break;
      }
    }
    return startIndex > endIndex ? [0, -1] : [startIndex, endIndex];
  }, [tabOffsets, visibleTabContentValue, tabContentSizeValue, addNodeSizeValue, operationNodeSizeValue, transformSize, tabPosition, tabs.map(tab => tab.key).join('_'), rtl]);
}