jtBaseApp/node_modules/@popperjs/core/lib/utils/computeOffsets.js

import getBasePlacement from "./getBasePlacement.js";
import getVariation from "./getVariation.js";
import getMainAxisFromPlacement from "./getMainAxisFromPlacement.js";
import { top, right, bottom, left, start, end } from "../enums.js";
export default function computeOffsets(_ref) {
  var reference = _ref.reference,
      element = _ref.element,
      placement = _ref.placement;
  var basePlacement = placement ? getBasePlacement(placement) : null;
  var variation = placement ? getVariation(placement) : null;
  var commonX = reference.x + reference.width / 2 - element.width / 2;
  var commonY = reference.y + reference.height / 2 - element.height / 2;
  var offsets;

  switch (basePlacement) {
    case top:
      offsets = {
        x: commonX,
        y: reference.y - element.height
      };
      break;

    case bottom:
      offsets = {
        x: commonX,
        y: reference.y + reference.height
      };
      break;

    case right:
      offsets = {
        x: reference.x + reference.width,
        y: commonY
      };
      break;

    case left:
      offsets = {
        x: reference.x - element.width,
        y: commonY
      };
      break;

    default:
      offsets = {
        x: reference.x,
        y: reference.y
      };
  }

  var mainAxis = basePlacement ? getMainAxisFromPlacement(basePlacement) : null;

  if (mainAxis != null) {
    var len = mainAxis === 'y' ? 'height' : 'width';

    switch (variation) {
      case start:
        offsets[mainAxis] = offsets[mainAxis] - (reference[len] / 2 - element[len] / 2);
        break;

      case end:
        offsets[mainAxis] = offsets[mainAxis] + (reference[len] / 2 - element[len] / 2);
        break;

      default:
    }
  }

  return offsets;
}