dom-helpers/cjs/position.js

tiny modular DOM lib for ie9+

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
exports.__esModule = true;
exports.default = position;
var _css = _interopRequireDefault(require("./css.js"));
var _offset = _interopRequireDefault(require("./offset.js"));
var _offsetParent = _interopRequireDefault(require("./offsetParent.js"));
var _scrollLeft = _interopRequireDefault(require("./scrollLeft.js"));
var _scrollTop = _interopRequireDefault(require("./scrollTop.js"));
const nodeName = node => node.nodeName && node.nodeName.toLowerCase();

/**
 * Returns the relative position of a given element.
 *
 * @param node the element
 * @param offsetParent the offset parent
 */
function position(node, offsetParent) {
  let parentOffset = {
    top: 0,
    left: 0
  };
  let offset;

  // Fixed elements are offset from window (parentOffset = {top:0, left: 0},
  // because it is its only offset parent
  if ((0, _css.default)(node, 'position') === 'fixed') {
    offset = node.getBoundingClientRect();
  } else {
    const parent = offsetParent || (0, _offsetParent.default)(node);
    offset = (0, _offset.default)(node);
    if (nodeName(parent) !== 'html') parentOffset = (0, _offset.default)(parent);
    const borderTop = String((0, _css.default)(parent, 'borderTopWidth') || 0);
    parentOffset.top += parseInt(borderTop, 10) - (0, _scrollTop.default)(parent) || 0;
    const borderLeft = String((0, _css.default)(parent, 'borderLeftWidth') || 0);
    parentOffset.left += parseInt(borderLeft, 10) - (0, _scrollLeft.default)(parent) || 0;
  }
  const marginTop = String((0, _css.default)(node, 'marginTop') || 0);
  const marginLeft = String((0, _css.default)(node, 'marginLeft') || 0);
  // Subtract parent offsets and node margins
  return {
    ...offset,
    top: offset.top - parentOffset.top - (parseInt(marginTop, 10) || 0),
    left: offset.left - parentOffset.left - (parseInt(marginLeft, 10) || 0)
  };
}
module.exports = exports.default;