react-dnd-html5-backend/dist/esm/EnterLeaveCounter.js

HTML5 backend for React DnD

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

import { union, without } from './utils/js_utils';
export var EnterLeaveCounter = /*#__PURE__*/function () {
  function EnterLeaveCounter(isNodeInDocument) {
    _classCallCheck(this, EnterLeaveCounter);

    _defineProperty(this, "entered", []);

    _defineProperty(this, "isNodeInDocument", void 0);

    this.isNodeInDocument = isNodeInDocument;
  }

  _createClass(EnterLeaveCounter, [{
    key: "enter",
    value: function enter(enteringNode) {
      var _this = this;

      var previousLength = this.entered.length;

      var isNodeEntered = function isNodeEntered(node) {
        return _this.isNodeInDocument(node) && (!node.contains || node.contains(enteringNode));
      };

      this.entered = union(this.entered.filter(isNodeEntered), [enteringNode]);
      return previousLength === 0 && this.entered.length > 0;
    }
  }, {
    key: "leave",
    value: function leave(leavingNode) {
      var previousLength = this.entered.length;
      this.entered = without(this.entered.filter(this.isNodeInDocument), leavingNode);
      return previousLength > 0 && this.entered.length === 0;
    }
  }, {
    key: "reset",
    value: function reset() {
      this.entered = [];
    }
  }]);

  return EnterLeaveCounter;
}();