text: import _classCallCheck from "@babel/runtime/helpers/classCallCheck";
  import _createClass from "@babel/runtime/helpers/createClass";
  import _inherits from "@babel/runtime/helpers/inherits";
  import _possibleConstructorReturn from "@babel/runtime/helpers/possibleConstructorReturn";
  import _getPrototypeOf from "@babel/runtime/helpers/getPrototypeOf";
  import _defineProperty from "@babel/runtime/helpers/defineProperty";
  
  function _createSuper(Derived) { return function () { var Super = _getPrototypeOf(Derived), result; if (_isNativeReflectConstruct()) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }
  
  function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }
  
  function _createForOfIteratorHelper(o) { if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) { if (Array.isArray(o) || (o = _unsupportedIterableToArray(o))) { var i = 0; var F = function F() {}; return { s: F, n: function n() { if (i >= o.length) return { done: true }; return { done: false, value: o[i++] }; }, e: function e(_e) { throw _e; }, f: F }; } throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); } var it, normalCompletion = true, didErr = false, err; return { s: function s() { it = o[Symbol.iterator](); }, n: function n() { var step = it.next(); normalCompletion = step.done; return step; }, e: function e(_e2) { didErr = true; err = _e2; }, f: function f() { try { if (!normalCompletion && it.return != null) it.return(); } finally { if (didErr) throw err; } } }; }
  
  function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(n); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }
  
  function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }
  
  import { Type } from '../constants';
  import { YAMLReferenceError } from '../errors';
  import { toJSON as _toJSON } from '../toJSON';
  import { Collection } from './Collection';
  import { Node } from './Node';
  import { Pair } from './Pair';
  
  var getAliasCount = function getAliasCount(node, anchors) {
    if (node instanceof Alias) {
      var anchor = anchors.get(node.source);
      return anchor.count * anchor.aliasCount;
    } else if (node instanceof Collection) {
      var count = 0;
  
      var _iterator = _createForOfIteratorHelper(node.items),
          _step;
  
      try {
        for (_iterator.s(); !(_step = _iterator.n()).done;) {
          var item = _step.value;
          var c = getAliasCount(item, anchors);
          if (c > count) count = c;
        }
      } catch (err) {
        _iterator.e(err);
      } finally {
        _iterator.f();
      }
  
      return count;
    } else if (node instanceof Pair) {
      var kc = getAliasCount(node.key, anchors);
      var vc = getAliasCount(node.value, anchors);
      return Math.max(kc, vc);
    }
  
    return 1;
  };
  
  export var Alias = /*#__PURE__*/function (_Node) {
    _inherits(Alias, _Node);
  
    var _super = _createSuper(Alias);
  
    _createClass(Alias, null, [{
      key: "stringify",
      value: function stringify(_ref, _ref2) {
        var range = _ref.range,
            source = _ref.source;
        var anchors = _ref2.anchors,
            doc = _ref2.doc,
            implicitKey = _ref2.implicitKey,
            inStringifyKey = _ref2.inStringifyKey;
        var anchor = Object.keys(anchors).find(function (a) {
          return anchors[a] === source;
        });
        if (!anchor && inStringifyKey) anchor = doc.anchors.getName(source) || doc.anchors.newName();
        if (anchor) return "*".concat(anchor).concat(implicitKey ? ' ' : '');
        var msg = doc.anchors.getName(source) ? 'Alias node must be after source node' : 'Source node not found for alias node';
        throw new Error("".concat(msg, " [").concat(range, "]"));
      }
    }]);
  
    function Alias(source) {
      var _this;
  
      _classCallCheck(this, Alias);
  
      _this = _super.call(this);
      _this.source = source;
      _this.type = Type.ALIAS;
      return _this;
    }
  
    _createClass(Alias, [{
      key: "toJSON",
      value: function toJSON(arg, ctx) {
        if (!ctx) return _toJSON(this.source, arg, ctx);
        var anchors = ctx.anchors,
            maxAliasCount = ctx.maxAliasCount;
        var anchor = anchors.get(this.source);
        /* istanbul ignore if */
  
        if (!anchor || anchor.res === undefined) {
          var msg = 'This should not happen: Alias anchor was not resolved?';
          if (this.cstNode) throw new YAMLReferenceError(this.cstNode, msg);else throw new ReferenceError(msg);
        }
  
        if (maxAliasCount >= 0) {
          anchor.count += 1;
          if (anchor.aliasCount === 0) anchor.aliasCount = getAliasCount(this.source, anchors);
  
          if (anchor.count * anchor.aliasCount > maxAliasCount) {
            var _msg = 'Excessive alias count indicates a resource exhaustion attack';
            if (this.cstNode) throw new YAMLReferenceError(this.cstNode, _msg);else throw new ReferenceError(_msg);
          }
        }
  
        return anchor.res;
      } // Only called when stringifying an alias mapping key while constructing
      // Object output.
  
    }, {
      key: "toString",
      value: function toString(ctx) {
        return Alias.stringify(this, ctx);
      }
    }, {
      key: "tag",
      set: function set(t) {
        throw new Error('Alias nodes cannot have tags');
      }
    }]);
  
    return Alias;
  }(Node);
  
  _defineProperty(Alias, "default", true);