@dagrejs/graphlib/dist/graphlib.core.js

A directed and undirected multi-graph library

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.graphlib = f()}})(function(){var define,module,exports;return (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
/**
 * Copyright (c) 2014, Chris Pettitt
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

var lib = require("./lib");

module.exports = {
  Graph: lib.Graph,
  json: require("./lib/json"),
  alg: require("./lib/alg"),
  version: lib.version
};

},{"./lib":17,"./lib/alg":8,"./lib/json":18}],2:[function(require,module,exports){
module.exports = components;

function components(g) {
  var visited = {};
  var cmpts = [];
  var cmpt;

  function dfs(v) {
    if (Object.hasOwn(visited, v)) return;
    visited[v] = true;
    cmpt.push(v);
    g.successors(v).forEach(dfs);
    g.predecessors(v).forEach(dfs);
  }

  g.nodes().forEach(function(v) {
    cmpt = [];
    dfs(v);
    if (cmpt.length) {
      cmpts.push(cmpt);
    }
  });

  return cmpts;
}

},{}],3:[function(require,module,exports){
module.exports = dfs;

/*
 * A helper that preforms a pre- or post-order traversal on the input graph
 * and returns the nodes in the order they were visited. If the graph is
 * undirected then this algorithm will navigate using neighbors. If the graph
 * is directed then this algorithm will navigate using successors.
 *
 * If the order is not "post", it will be treated as "pre".
 */
function dfs(g, vs, order) {
  if (!Array.isArray(vs)) {
    vs = [vs];
  }

  var navigation = g.isDirected() ? v => g.successors(v) : v => g.neighbors(v);
  var orderFunc = order === "post" ? postOrderDfs : preOrderDfs;

  var acc = [];
  var visited = {};
  vs.forEach(v => {
    if (!g.hasNode(v)) {
      throw new Error("Graph does not have node: " + v);
    }

    orderFunc(v, navigation, visited, acc);
  });

  return acc;
}

function postOrderDfs(v, navigation, visited, acc) {
  var stack = [[v, false]];
  while (stack.length > 0) {
    var curr = stack.pop();
    if (curr[1]) {
      acc.push(curr[0]);
    } else {
      if (!Object.hasOwn(visited, curr[0])) {
        visited[curr[0]] = true;
        stack.push([curr[0], true]);
        forEachRight(navigation(curr[0]), w => stack.push([w, false]));
      }
    }
  }
}

function preOrderDfs(v, navigation, visited, acc) {
  var stack = [v];
  while (stack.length > 0) {
    var curr = stack.pop();
    if (!Object.hasOwn(visited, curr)) {
      visited[curr] = true;
      acc.push(curr);
      forEachRight(navigation(curr), w => stack.push(w));
    }
  }
}

function forEachRight(array, iteratee) {
  var length = array.length;
  while (length--) {
    iteratee(array[length], length, array);
  }

  return array;
}

},{}],4:[function(require,module,exports){
var dijkstra = require("./dijkstra");

module.exports = dijkstraAll;

function dijkstraAll(g, weightFunc, edgeFunc) {
  return g.nodes().reduce(function(acc, v) {
    acc[v] = dijkstra(g, v, weightFunc, edgeFunc);
    return acc;
  }, {});
}

},{"./dijkstra":5}],5:[function(require,module,exports){
var PriorityQueue = require("../data/priority-queue");

module.exports = dijkstra;

var DEFAULT_WEIGHT_FUNC = () => 1;

function dijkstra(g, source, weightFn, edgeFn) {
  return runDijkstra(g, String(source),
    weightFn || DEFAULT_WEIGHT_FUNC,
    edgeFn || function(v) { return g.outEdges(v); });
}

function runDijkstra(g, source, weightFn, edgeFn) {
  var results = {};
  var pq = new PriorityQueue();
  var v, vEntry;

  var updateNeighbors = function(edge) {
    var w = edge.v !== v ? edge.v : edge.w;
    var wEntry = results[w];
    var weight = weightFn(edge);
    var distance = vEntry.distance + weight;

    if (weight < 0) {
      throw new Error("dijkstra does not allow negative edge weights. " +
                      "Bad edge: " + edge + " Weight: " + weight);
    }

    if (distance < wEntry.distance) {
      wEntry.distance = distance;
      wEntry.predecessor = v;
      pq.decrease(w, distance);
    }
  };

  g.nodes().forEach(function(v) {
    var distance = v === source ? 0 : Number.POSITIVE_INFINITY;
    results[v] = { distance: distance };
    pq.add(v, distance);
  });

  while (pq.size() > 0) {
    v = pq.removeMin();
    vEntry = results[v];
    if (vEntry.distance === Number.POSITIVE_INFINITY) {
      break;
    }

    edgeFn(v).forEach(updateNeighbors);
  }

  return results;
}

},{"../data/priority-queue":15}],6:[function(require,module,exports){
var tarjan = require("./tarjan");

module.exports = findCycles;

function findCycles(g) {
  return tarjan(g).filter(function(cmpt) {
    return cmpt.length > 1 || (cmpt.length === 1 && g.hasEdge(cmpt[0], cmpt[0]));
  });
}

},{"./tarjan":13}],7:[function(require,module,exports){
module.exports = floydWarshall;

var DEFAULT_WEIGHT_FUNC = () => 1;

function floydWarshall(g, weightFn, edgeFn) {
  return runFloydWarshall(g,
    weightFn || DEFAULT_WEIGHT_FUNC,
    edgeFn || function(v) { return g.outEdges(v); });
}

function runFloydWarshall(g, weightFn, edgeFn) {
  var results = {};
  var nodes = g.nodes();

  nodes.forEach(function(v) {
    results[v] = {};
    results[v][v] = { distance: 0 };
    nodes.forEach(function(w) {
      if (v !== w) {
        results[v][w] = { distance: Number.POSITIVE_INFINITY };
      }
    });
    edgeFn(v).forEach(function(edge) {
      var w = edge.v === v ? edge.w : edge.v;
      var d = weightFn(edge);
      results[v][w] = { distance: d, predecessor: v };
    });
  });

  nodes.forEach(function(k) {
    var rowK = results[k];
    nodes.forEach(function(i) {
      var rowI = results[i];
      nodes.forEach(function(j) {
        var ik = rowI[k];
        var kj = rowK[j];
        var ij = rowI[j];
        var altDistance = ik.distance + kj.distance;
        if (altDistance < ij.distance) {
          ij.distance = altDistance;
          ij.predecessor = kj.predecessor;
        }
      });
    });
  });

  return results;
}

},{}],8:[function(require,module,exports){
module.exports = {
  components: require("./components"),
  dijkstra: require("./dijkstra"),
  dijkstraAll: require("./dijkstra-all"),
  findCycles: require("./find-cycles"),
  floydWarshall: require("./floyd-warshall"),
  isAcyclic: require("./is-acyclic"),
  postorder: require("./postorder"),
  preorder: require("./preorder"),
  prim: require("./prim"),
  tarjan: require("./tarjan"),
  topsort: require("./topsort")
};

},{"./components":2,"./dijkstra":5,"./dijkstra-all":4,"./find-cycles":6,"./floyd-warshall":7,"./is-acyclic":9,"./postorder":10,"./preorder":11,"./prim":12,"./tarjan":13,"./topsort":14}],9:[function(require,module,exports){
var topsort = require("./topsort");

module.exports = isAcyclic;

function isAcyclic(g) {
  try {
    topsort(g);
  } catch (e) {
    if (e instanceof topsort.CycleException) {
      return false;
    }
    throw e;
  }
  return true;
}

},{"./topsort":14}],10:[function(require,module,exports){
var dfs = require("./dfs");

module.exports = postorder;

function postorder(g, vs) {
  return dfs(g, vs, "post");
}

},{"./dfs":3}],11:[function(require,module,exports){
var dfs = require("./dfs");

module.exports = preorder;

function preorder(g, vs) {
  return dfs(g, vs, "pre");
}

},{"./dfs":3}],12:[function(require,module,exports){
var Graph = require("../graph");
var PriorityQueue = require("../data/priority-queue");

module.exports = prim;

function prim(g, weightFunc) {
  var result = new Graph();
  var parents = {};
  var pq = new PriorityQueue();
  var v;

  function updateNeighbors(edge) {
    var w = edge.v === v ? edge.w : edge.v;
    var pri = pq.priority(w);
    if (pri !== undefined) {
      var edgeWeight = weightFunc(edge);
      if (edgeWeight < pri) {
        parents[w] = v;
        pq.decrease(w, edgeWeight);
      }
    }
  }

  if (g.nodeCount() === 0) {
    return result;
  }

  g.nodes().forEach(function(v) {
    pq.add(v, Number.POSITIVE_INFINITY);
    result.setNode(v);
  });

  // Start from an arbitrary node
  pq.decrease(g.nodes()[0], 0);

  var init = false;
  while (pq.size() > 0) {
    v = pq.removeMin();
    if (Object.hasOwn(parents, v)) {
      result.setEdge(v, parents[v]);
    } else if (init) {
      throw new Error("Input graph is not connected: " + g);
    } else {
      init = true;
    }

    g.nodeEdges(v).forEach(updateNeighbors);
  }

  return result;
}

},{"../data/priority-queue":15,"../graph":16}],13:[function(require,module,exports){
module.exports = tarjan;

function tarjan(g) {
  var index = 0;
  var stack = [];
  var visited = {}; // node id -> { onStack, lowlink, index }
  var results = [];

  function dfs(v) {
    var entry = visited[v] = {
      onStack: true,
      lowlink: index,
      index: index++
    };
    stack.push(v);

    g.successors(v).forEach(function(w) {
      if (!Object.hasOwn(visited, w)) {
        dfs(w);
        entry.lowlink = Math.min(entry.lowlink, visited[w].lowlink);
      } else if (visited[w].onStack) {
        entry.lowlink = Math.min(entry.lowlink, visited[w].index);
      }
    });

    if (entry.lowlink === entry.index) {
      var cmpt = [];
      var w;
      do {
        w = stack.pop();
        visited[w].onStack = false;
        cmpt.push(w);
      } while (v !== w);
      results.push(cmpt);
    }
  }

  g.nodes().forEach(function(v) {
    if (!Object.hasOwn(visited, v)) {
      dfs(v);
    }
  });

  return results;
}

},{}],14:[function(require,module,exports){
function topsort(g) {
  var visited = {};
  var stack = {};
  var results = [];

  function visit(node) {
    if (Object.hasOwn(stack, node)) {
      throw new CycleException();
    }

    if (!Object.hasOwn(visited, node)) {
      stack[node] = true;
      visited[node] = true;
      g.predecessors(node).forEach(visit);
      delete stack[node];
      results.push(node);
    }
  }

  g.sinks().forEach(visit);

  if (Object.keys(visited).length !== g.nodeCount()) {
    throw new CycleException();
  }

  return results;
}

class CycleException extends Error {
  constructor() {
    super(...arguments);
  }
}

module.exports = topsort;
topsort.CycleException = CycleException;

},{}],15:[function(require,module,exports){
/**
 * A min-priority queue data structure. This algorithm is derived from Cormen,
 * et al., "Introduction to Algorithms". The basic idea of a min-priority
 * queue is that you can efficiently (in O(1) time) get the smallest key in
 * the queue. Adding and removing elements takes O(log n) time. A key can
 * have its priority decreased in O(log n) time.
 */
class PriorityQueue {
  _arr = [];
  _keyIndices = {};

  /**
   * Returns the number of elements in the queue. Takes `O(1)` time.
   */
  size() {
    return this._arr.length;
  }

  /**
   * Returns the keys that are in the queue. Takes `O(n)` time.
   */
  keys() {
    return this._arr.map(function(x) { return x.key; });
  }

  /**
   * Returns `true` if **key** is in the queue and `false` if not.
   */
  has(key) {
    return Object.hasOwn(this._keyIndices, key);
  }

  /**
   * Returns the priority for **key**. If **key** is not present in the queue
   * then this function returns `undefined`. Takes `O(1)` time.
   *
   * @param {Object} key
   */
  priority(key) {
    var index = this._keyIndices[key];
    if (index !== undefined) {
      return this._arr[index].priority;
    }
  }

  /**
   * Returns the key for the minimum element in this queue. If the queue is
   * empty this function throws an Error. Takes `O(1)` time.
   */
  min() {
    if (this.size() === 0) {
      throw new Error("Queue underflow");
    }
    return this._arr[0].key;
  }

  /**
   * Inserts a new key into the priority queue. If the key already exists in
   * the queue this function returns `false`; otherwise it will return `true`.
   * Takes `O(n)` time.
   *
   * @param {Object} key the key to add
   * @param {Number} priority the initial priority for the key
   */
  add(key, priority) {
    var keyIndices = this._keyIndices;
    key = String(key);
    if (!Object.hasOwn(keyIndices, key)) {
      var arr = this._arr;
      var index = arr.length;
      keyIndices[key] = index;
      arr.push({key: key, priority: priority});
      this._decrease(index);
      return true;
    }
    return false;
  }

  /**
   * Removes and returns the smallest key in the queue. Takes `O(log n)` time.
   */
  removeMin() {
    this._swap(0, this._arr.length - 1);
    var min = this._arr.pop();
    delete this._keyIndices[min.key];
    this._heapify(0);
    return min.key;
  }

  /**
   * Decreases the priority for **key** to **priority**. If the new priority is
   * greater than the previous priority, this function will throw an Error.
   *
   * @param {Object} key the key for which to raise priority
   * @param {Number} priority the new priority for the key
   */
  decrease(key, priority) {
    var index = this._keyIndices[key];
    if (priority > this._arr[index].priority) {
      throw new Error("New priority is greater than current priority. " +
          "Key: " + key + " Old: " + this._arr[index].priority + " New: " + priority);
    }
    this._arr[index].priority = priority;
    this._decrease(index);
  }

  _heapify(i) {
    var arr = this._arr;
    var l = 2 * i;
    var r = l + 1;
    var largest = i;
    if (l < arr.length) {
      largest = arr[l].priority < arr[largest].priority ? l : largest;
      if (r < arr.length) {
        largest = arr[r].priority < arr[largest].priority ? r : largest;
      }
      if (largest !== i) {
        this._swap(i, largest);
        this._heapify(largest);
      }
    }
  }

  _decrease(index) {
    var arr = this._arr;
    var priority = arr[index].priority;
    var parent;
    while (index !== 0) {
      parent = index >> 1;
      if (arr[parent].priority < priority) {
        break;
      }
      this._swap(index, parent);
      index = parent;
    }
  }

  _swap(i, j) {
    var arr = this._arr;
    var keyIndices = this._keyIndices;
    var origArrI = arr[i];
    var origArrJ = arr[j];
    arr[i] = origArrJ;
    arr[j] = origArrI;
    keyIndices[origArrJ.key] = i;
    keyIndices[origArrI.key] = j;
  }
}

module.exports = PriorityQueue;

},{}],16:[function(require,module,exports){
"use strict";

var DEFAULT_EDGE_NAME = "\x00";
var GRAPH_NODE = "\x00";
var EDGE_KEY_DELIM = "\x01";

// Implementation notes:
//
//  * Node id query functions should return string ids for the nodes
//  * Edge id query functions should return an "edgeObj", edge object, that is
//    composed of enough information to uniquely identify an edge: {v, w, name}.
//  * Internally we use an "edgeId", a stringified form of the edgeObj, to
//    reference edges. This is because we need a performant way to look these
//    edges up and, object properties, which have string keys, are the closest
//    we're going to get to a performant hashtable in JavaScript.

class Graph {
  _isDirected = true;
  _isMultigraph = false;
  _isCompound = false;

  // Label for the graph itself
  _label;

  // Defaults to be set when creating a new node
  _defaultNodeLabelFn = () => undefined;

  // Defaults to be set when creating a new edge
  _defaultEdgeLabelFn = () => undefined;

  // v -> label
  _nodes = {};

  // v -> edgeObj
  _in = {};

  // u -> v -> Number
  _preds = {};

  // v -> edgeObj
  _out = {};

  // v -> w -> Number
  _sucs = {};

  // e -> edgeObj
  _edgeObjs = {};

  // e -> label
  _edgeLabels = {};

  /* Number of nodes in the graph. Should only be changed by the implementation. */
  _nodeCount = 0;

  /* Number of edges in the graph. Should only be changed by the implementation. */
  _edgeCount = 0;

  _parent;

  _children;

  constructor(opts) {
    if (opts) {
      this._isDirected = Object.hasOwn(opts, "directed") ? opts.directed : true;
      this._isMultigraph = Object.hasOwn(opts, "multigraph") ? opts.multigraph : false;
      this._isCompound = Object.hasOwn(opts, "compound") ? opts.compound : false;
    }

    if (this._isCompound) {
      // v -> parent
      this._parent = {};

      // v -> children
      this._children = {};
      this._children[GRAPH_NODE] = {};
    }
  }

  /* === Graph functions ========= */

  /**
   * Whether graph was created with 'directed' flag set to true or not.
   */
  isDirected() {
    return this._isDirected;
  }

  /**
   * Whether graph was created with 'multigraph' flag set to true or not.
   */
  isMultigraph() {
    return this._isMultigraph;
  }

  /**
   * Whether graph was created with 'compound' flag set to true or not.
   */
  isCompound() {
    return this._isCompound;
  }

  /**
   * Sets the label of the graph.
   */
  setGraph(label) {
    this._label = label;
    return this;
  }

  /**
   * Gets the graph label.
   */
  graph() {
    return this._label;
  }


  /* === Node functions ========== */

  /**
   * Sets the default node label. If newDefault is a function, it will be
   * invoked ach time when setting a label for a node. Otherwise, this label
   * will be assigned as default label in case if no label was specified while
   * setting a node.
   * Complexity: O(1).
   */
  setDefaultNodeLabel(newDefault) {
    this._defaultNodeLabelFn = newDefault;
    if (typeof newDefault !== 'function') {
      this._defaultNodeLabelFn = () => newDefault;
    }

    return this;
  }

  /**
   * Gets the number of nodes in the graph.
   * Complexity: O(1).
   */
  nodeCount() {
    return this._nodeCount;
  }

  /**
   * Gets all nodes of the graph. Note, the in case of compound graph subnodes are
   * not included in list.
   * Complexity: O(1).
   */
  nodes() {
    return Object.keys(this._nodes);
  }

  /**
   * Gets list of nodes without in-edges.
   * Complexity: O(|V|).
   */
  sources() {
    var self = this;
    return this.nodes().filter(v => Object.keys(self._in[v]).length === 0);
  }

  /**
   * Gets list of nodes without out-edges.
   * Complexity: O(|V|).
   */
  sinks() {
    var self = this;
    return this.nodes().filter(v => Object.keys(self._out[v]).length === 0);
  }

  /**
   * Invokes setNode method for each node in names list.
   * Complexity: O(|names|).
   */
  setNodes(vs, value) {
    var args = arguments;
    var self = this;
    vs.forEach(function(v) {
      if (args.length > 1) {
        self.setNode(v, value);
      } else {
        self.setNode(v);
      }
    });
    return this;
  }

  /**
   * Creates or updates the value for the node v in the graph. If label is supplied
   * it is set as the value for the node. If label is not supplied and the node was
   * created by this call then the default node label will be assigned.
   * Complexity: O(1).
   */
  setNode(v, value) {
    if (Object.hasOwn(this._nodes, v)) {
      if (arguments.length > 1) {
        this._nodes[v] = value;
      }
      return this;
    }

    this._nodes[v] = arguments.length > 1 ? value : this._defaultNodeLabelFn(v);
    if (this._isCompound) {
      this._parent[v] = GRAPH_NODE;
      this._children[v] = {};
      this._children[GRAPH_NODE][v] = true;
    }
    this._in[v] = {};
    this._preds[v] = {};
    this._out[v] = {};
    this._sucs[v] = {};
    ++this._nodeCount;
    return this;
  }

  /**
   * Gets the label of node with specified name.
   * Complexity: O(|V|).
   */
  node(v) {
    return this._nodes[v];
  }

  /**
   * Detects whether graph has a node with specified name or not.
   */
  hasNode(v) {
    return Object.hasOwn(this._nodes, v);
  }

  /**
   * Remove the node with the name from the graph or do nothing if the node is not in
   * the graph. If the node was removed this function also removes any incident
   * edges.
   * Complexity: O(1).
   */
  removeNode(v) {
    var self = this;
    if (Object.hasOwn(this._nodes, v)) {
      var removeEdge = e => self.removeEdge(self._edgeObjs[e]);
      delete this._nodes[v];
      if (this._isCompound) {
        this._removeFromParentsChildList(v);
        delete this._parent[v];
        this.children(v).forEach(function(child) {
          self.setParent(child);
        });
        delete this._children[v];
      }
      Object.keys(this._in[v]).forEach(removeEdge);
      delete this._in[v];
      delete this._preds[v];
      Object.keys(this._out[v]).forEach(removeEdge);
      delete this._out[v];
      delete this._sucs[v];
      --this._nodeCount;
    }
    return this;
  }

  /**
   * Sets node p as a parent for node v if it is defined, or removes the
   * parent for v if p is undefined. Method throws an exception in case of
   * invoking it in context of noncompound graph.
   * Average-case complexity: O(1).
   */
  setParent(v, parent) {
    if (!this._isCompound) {
      throw new Error("Cannot set parent in a non-compound graph");
    }

    if (parent === undefined) {
      parent = GRAPH_NODE;
    } else {
      // Coerce parent to string
      parent += "";
      for (var ancestor = parent; ancestor !== undefined; ancestor = this.parent(ancestor)) {
        if (ancestor === v) {
          throw new Error("Setting " + parent+ " as parent of " + v +
              " would create a cycle");
        }
      }

      this.setNode(parent);
    }

    this.setNode(v);
    this._removeFromParentsChildList(v);
    this._parent[v] = parent;
    this._children[parent][v] = true;
    return this;
  }

  _removeFromParentsChildList(v) {
    delete this._children[this._parent[v]][v];
  }

  /**
   * Gets parent node for node v.
   * Complexity: O(1).
   */
  parent(v) {
    if (this._isCompound) {
      var parent = this._parent[v];
      if (parent !== GRAPH_NODE) {
        return parent;
      }
    }
  }

  /**
   * Gets list of direct children of node v.
   * Complexity: O(1).
   */
  children(v = GRAPH_NODE) {
    if (this._isCompound) {
      var children = this._children[v];
      if (children) {
        return Object.keys(children);
      }
    } else if (v === GRAPH_NODE) {
      return this.nodes();
    } else if (this.hasNode(v)) {
      return [];
    }
  }

  /**
   * Return all nodes that are predecessors of the specified node or undefined if node v is not in
   * the graph. Behavior is undefined for undirected graphs - use neighbors instead.
   * Complexity: O(|V|).
   */
  predecessors(v) {
    var predsV = this._preds[v];
    if (predsV) {
      return Object.keys(predsV);
    }
  }

  /**
   * Return all nodes that are successors of the specified node or undefined if node v is not in
   * the graph. Behavior is undefined for undirected graphs - use neighbors instead.
   * Complexity: O(|V|).
   */
  successors(v) {
    var sucsV = this._sucs[v];
    if (sucsV) {
      return Object.keys(sucsV);
    }
  }

  /**
   * Return all nodes that are predecessors or successors of the specified node or undefined if
   * node v is not in the graph.
   * Complexity: O(|V|).
   */
  neighbors(v) {
    var preds = this.predecessors(v);
    if (preds) {
      const union = new Set(preds);
      for (var succ of this.successors(v)) {
        union.add(succ);
      }

      return Array.from(union.values());
    }
  }

  isLeaf(v) {
    var neighbors;
    if (this.isDirected()) {
      neighbors = this.successors(v);
    } else {
      neighbors = this.neighbors(v);
    }
    return neighbors.length === 0;
  }

  /**
   * Creates new graph with nodes filtered via filter. Edges incident to rejected node
   * are also removed. In case of compound graph, if parent is rejected by filter,
   * than all its children are rejected too.
   * Average-case complexity: O(|E|+|V|).
   */
  filterNodes(filter) {
    var copy = new this.constructor({
      directed: this._isDirected,
      multigraph: this._isMultigraph,
      compound: this._isCompound
    });

    copy.setGraph(this.graph());

    var self = this;
    Object.entries(this._nodes).forEach(function([v, value]) {
      if (filter(v)) {
        copy.setNode(v, value);
      }
    });

    Object.values(this._edgeObjs).forEach(function(e) {
      if (copy.hasNode(e.v) && copy.hasNode(e.w)) {
        copy.setEdge(e, self.edge(e));
      }
    });

    var parents = {};
    function findParent(v) {
      var parent = self.parent(v);
      if (parent === undefined || copy.hasNode(parent)) {
        parents[v] = parent;
        return parent;
      } else if (parent in parents) {
        return parents[parent];
      } else {
        return findParent(parent);
      }
    }

    if (this._isCompound) {
      copy.nodes().forEach(v => copy.setParent(v, findParent(v)));
    }

    return copy;
  }

  /* === Edge functions ========== */

  /**
   * Sets the default edge label or factory function. This label will be
   * assigned as default label in case if no label was specified while setting
   * an edge or this function will be invoked each time when setting an edge
   * with no label specified and returned value * will be used as a label for edge.
   * Complexity: O(1).
   */
  setDefaultEdgeLabel(newDefault) {
    this._defaultEdgeLabelFn = newDefault;
    if (typeof newDefault !== 'function') {
      this._defaultEdgeLabelFn = () => newDefault;
    }

    return this;
  }

  /**
   * Gets the number of edges in the graph.
   * Complexity: O(1).
   */
  edgeCount() {
    return this._edgeCount;
  }

  /**
   * Gets edges of the graph. In case of compound graph subgraphs are not considered.
   * Complexity: O(|E|).
   */
  edges() {
    return Object.values(this._edgeObjs);
  }

  /**
   * Establish an edges path over the nodes in nodes list. If some edge is already
   * exists, it will update its label, otherwise it will create an edge between pair
   * of nodes with label provided or default label if no label provided.
   * Complexity: O(|nodes|).
   */
  setPath(vs, value) {
    var self = this;
    var args = arguments;
    vs.reduce(function(v, w) {
      if (args.length > 1) {
        self.setEdge(v, w, value);
      } else {
        self.setEdge(v, w);
      }
      return w;
    });
    return this;
  }

  /**
   * Creates or updates the label for the edge (v, w) with the optionally supplied
   * name. If label is supplied it is set as the value for the edge. If label is not
   * supplied and the edge was created by this call then the default edge label will
   * be assigned. The name parameter is only useful with multigraphs.
   */
  setEdge() {
    var v, w, name, value;
    var valueSpecified = false;
    var arg0 = arguments[0];

    if (typeof arg0 === "object" && arg0 !== null && "v" in arg0) {
      v = arg0.v;
      w = arg0.w;
      name = arg0.name;
      if (arguments.length === 2) {
        value = arguments[1];
        valueSpecified = true;
      }
    } else {
      v = arg0;
      w = arguments[1];
      name = arguments[3];
      if (arguments.length > 2) {
        value = arguments[2];
        valueSpecified = true;
      }
    }

    v = "" + v;
    w = "" + w;
    if (name !== undefined) {
      name = "" + name;
    }

    var e = edgeArgsToId(this._isDirected, v, w, name);
    if (Object.hasOwn(this._edgeLabels, e)) {
      if (valueSpecified) {
        this._edgeLabels[e] = value;
      }
      return this;
    }

    if (name !== undefined && !this._isMultigraph) {
      throw new Error("Cannot set a named edge when isMultigraph = false");
    }

    // It didn't exist, so we need to create it.
    // First ensure the nodes exist.
    this.setNode(v);
    this.setNode(w);

    this._edgeLabels[e] = valueSpecified ? value : this._defaultEdgeLabelFn(v, w, name);

    var edgeObj = edgeArgsToObj(this._isDirected, v, w, name);
    // Ensure we add undirected edges in a consistent way.
    v = edgeObj.v;
    w = edgeObj.w;

    Object.freeze(edgeObj);
    this._edgeObjs[e] = edgeObj;
    incrementOrInitEntry(this._preds[w], v);
    incrementOrInitEntry(this._sucs[v], w);
    this._in[w][e] = edgeObj;
    this._out[v][e] = edgeObj;
    this._edgeCount++;
    return this;
  }

  /**
   * Gets the label for the specified edge.
   * Complexity: O(1).
   */
  edge(v, w, name) {
    var e = (arguments.length === 1
      ? edgeObjToId(this._isDirected, arguments[0])
      : edgeArgsToId(this._isDirected, v, w, name));
    return this._edgeLabels[e];
  }

  /**
   * Gets the label for the specified edge and converts it to an object.
   * Complexity: O(1)
   */
  edgeAsObj() {
    const edge = this.edge(...arguments);
    if (typeof edge !== "object") {
      return {label: edge};
    }

    return edge;
  }

  /**
   * Detects whether the graph contains specified edge or not. No subgraphs are considered.
   * Complexity: O(1).
   */
  hasEdge(v, w, name) {
    var e = (arguments.length === 1
      ? edgeObjToId(this._isDirected, arguments[0])
      : edgeArgsToId(this._isDirected, v, w, name));
    return Object.hasOwn(this._edgeLabels, e);
  }

  /**
   * Removes the specified edge from the graph. No subgraphs are considered.
   * Complexity: O(1).
   */
  removeEdge(v, w, name) {
    var e = (arguments.length === 1
      ? edgeObjToId(this._isDirected, arguments[0])
      : edgeArgsToId(this._isDirected, v, w, name));
    var edge = this._edgeObjs[e];
    if (edge) {
      v = edge.v;
      w = edge.w;
      delete this._edgeLabels[e];
      delete this._edgeObjs[e];
      decrementOrRemoveEntry(this._preds[w], v);
      decrementOrRemoveEntry(this._sucs[v], w);
      delete this._in[w][e];
      delete this._out[v][e];
      this._edgeCount--;
    }
    return this;
  }

  /**
   * Return all edges that point to the node v. Optionally filters those edges down to just those
   * coming from node u. Behavior is undefined for undirected graphs - use nodeEdges instead.
   * Complexity: O(|E|).
   */
  inEdges(v, u) {
    var inV = this._in[v];
    if (inV) {
      var edges = Object.values(inV);
      if (!u) {
        return edges;
      }
      return edges.filter(edge => edge.v === u);
    }
  }

  /**
   * Return all edges that are pointed at by node v. Optionally filters those edges down to just
   * those point to w. Behavior is undefined for undirected graphs - use nodeEdges instead.
   * Complexity: O(|E|).
   */
  outEdges(v, w) {
    var outV = this._out[v];
    if (outV) {
      var edges = Object.values(outV);
      if (!w) {
        return edges;
      }
      return edges.filter(edge => edge.w === w);
    }
  }

  /**
   * Returns all edges to or from node v regardless of direction. Optionally filters those edges
   * down to just those between nodes v and w regardless of direction.
   * Complexity: O(|E|).
   */
  nodeEdges(v, w) {
    var inEdges = this.inEdges(v, w);
    if (inEdges) {
      return inEdges.concat(this.outEdges(v, w));
    }
  }
}

function incrementOrInitEntry(map, k) {
  if (map[k]) {
    map[k]++;
  } else {
    map[k] = 1;
  }
}

function decrementOrRemoveEntry(map, k) {
  if (!--map[k]) { delete map[k]; }
}

function edgeArgsToId(isDirected, v_, w_, name) {
  var v = "" + v_;
  var w = "" + w_;
  if (!isDirected && v > w) {
    var tmp = v;
    v = w;
    w = tmp;
  }
  return v + EDGE_KEY_DELIM + w + EDGE_KEY_DELIM +
             (name === undefined ? DEFAULT_EDGE_NAME : name);
}

function edgeArgsToObj(isDirected, v_, w_, name) {
  var v = "" + v_;
  var w = "" + w_;
  if (!isDirected && v > w) {
    var tmp = v;
    v = w;
    w = tmp;
  }
  var edgeObj =  { v: v, w: w };
  if (name) {
    edgeObj.name = name;
  }
  return edgeObj;
}

function edgeObjToId(isDirected, edgeObj) {
  return edgeArgsToId(isDirected, edgeObj.v, edgeObj.w, edgeObj.name);
}

module.exports = Graph;

},{}],17:[function(require,module,exports){
// Includes only the "core" of graphlib
module.exports = {
  Graph: require("./graph"),
  version: require("./version")
};

},{"./graph":16,"./version":19}],18:[function(require,module,exports){
var Graph = require("./graph");

module.exports = {
  write: write,
  read: read
};

/**
 * Creates a JSON representation of the graph that can be serialized to a string with
 * JSON.stringify. The graph can later be restored using json.read.
 */
function write(g) {
  var json = {
    options: {
      directed: g.isDirected(),
      multigraph: g.isMultigraph(),
      compound: g.isCompound()
    },
    nodes: writeNodes(g),
    edges: writeEdges(g)
  };

  if (g.graph() !== undefined) {
    json.value = structuredClone(g.graph());
  }
  return json;
}

function writeNodes(g) {
  return g.nodes().map(function(v) {
    var nodeValue = g.node(v);
    var parent = g.parent(v);
    var node = { v: v };
    if (nodeValue !== undefined) {
      node.value = nodeValue;
    }
    if (parent !== undefined) {
      node.parent = parent;
    }
    return node;
  });
}

function writeEdges(g) {
  return g.edges().map(function(e) {
    var edgeValue = g.edge(e);
    var edge = { v: e.v, w: e.w };
    if (e.name !== undefined) {
      edge.name = e.name;
    }
    if (edgeValue !== undefined) {
      edge.value = edgeValue;
    }
    return edge;
  });
}

/**
 * Takes JSON as input and returns the graph representation.
 *
 * @example
 * var g2 = graphlib.json.read(JSON.parse(str));
 * g2.nodes();
 * // ['a', 'b']
 * g2.edges()
 * // [ { v: 'a', w: 'b' } ]
 */
function read(json) {
  var g = new Graph(json.options).setGraph(json.value);
  json.nodes.forEach(function(entry) {
    g.setNode(entry.v, entry.value);
    if (entry.parent) {
      g.setParent(entry.v, entry.parent);
    }
  });
  json.edges.forEach(function(entry) {
    g.setEdge({ v: entry.v, w: entry.w, name: entry.name }, entry.value);
  });
  return g;
}

},{"./graph":16}],19:[function(require,module,exports){
module.exports = '2.2.4';

},{}]},{},[1])(1)
});