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- 'use strict';
- /**
- * @module symbol-tree
- * @author Joris van der Wel <joris@jorisvanderwel.com>
- */
- const SymbolTreeNode = require('./SymbolTreeNode');
- const TreePosition = require('./TreePosition');
- const TreeIterator = require('./TreeIterator');
- function returnTrue() {
- return true;
- }
- function reverseArrayIndex(array, reverseIndex) {
- return array[array.length - 1 - reverseIndex]; // no need to check `index >= 0`
- }
- class SymbolTree {
- /**
- * @constructor
- * @alias module:symbol-tree
- * @param {string} [description='SymbolTree data'] Description used for the Symbol
- */
- constructor(description) {
- this.symbol = Symbol(description || 'SymbolTree data');
- }
- /**
- * You can use this function to (optionally) initialize an object right after its creation,
- * to take advantage of V8's fast properties. Also useful if you would like to
- * freeze your object.
- *
- * `O(1)`
- *
- * @method
- * @alias module:symbol-tree#initialize
- * @param {Object} object
- * @return {Object} object
- */
- initialize(object) {
- this._node(object);
- return object;
- }
- _node(object) {
- if (!object) {
- return null;
- }
- const node = object[this.symbol];
- if (node) {
- return node;
- }
- return (object[this.symbol] = new SymbolTreeNode());
- }
- /**
- * Returns `true` if the object has any children. Otherwise it returns `false`.
- *
- * * `O(1)`
- *
- * @method hasChildren
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Boolean}
- */
- hasChildren(object) {
- return this._node(object).hasChildren;
- }
- /**
- * Returns the first child of the given object.
- *
- * * `O(1)`
- *
- * @method firstChild
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object}
- */
- firstChild(object) {
- return this._node(object).firstChild;
- }
- /**
- * Returns the last child of the given object.
- *
- * * `O(1)`
- *
- * @method lastChild
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object}
- */
- lastChild(object) {
- return this._node(object).lastChild;
- }
- /**
- * Returns the previous sibling of the given object.
- *
- * * `O(1)`
- *
- * @method previousSibling
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object}
- */
- previousSibling(object) {
- return this._node(object).previousSibling;
- }
- /**
- * Returns the next sibling of the given object.
- *
- * * `O(1)`
- *
- * @method nextSibling
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object}
- */
- nextSibling(object) {
- return this._node(object).nextSibling;
- }
- /**
- * Return the parent of the given object.
- *
- * * `O(1)`
- *
- * @method parent
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object}
- */
- parent(object) {
- return this._node(object).parent;
- }
- /**
- * Find the inclusive descendant that is last in tree order of the given object.
- *
- * * `O(n)` (worst case) where `n` is the depth of the subtree of `object`
- *
- * @method lastInclusiveDescendant
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object}
- */
- lastInclusiveDescendant(object) {
- let lastChild;
- let current = object;
- while ((lastChild = this._node(current).lastChild)) {
- current = lastChild;
- }
- return current;
- }
- /**
- * Find the preceding object (A) of the given object (B).
- * An object A is preceding an object B if A and B are in the same tree
- * and A comes before B in tree order.
- *
- * * `O(n)` (worst case)
- * * `O(1)` (amortized when walking the entire tree)
- *
- * @method preceding
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @param {Object} [options]
- * @param {Object} [options.root] If set, `root` must be an inclusive ancestor
- * of the return value (or else null is returned). This check _assumes_
- * that `root` is also an inclusive ancestor of the given `object`
- * @return {?Object}
- */
- preceding(object, options) {
- const treeRoot = options && options.root;
- if (object === treeRoot) {
- return null;
- }
- const previousSibling = this._node(object).previousSibling;
- if (previousSibling) {
- return this.lastInclusiveDescendant(previousSibling);
- }
- // if there is no previous sibling return the parent (might be null)
- return this._node(object).parent;
- }
- /**
- * Find the following object (A) of the given object (B).
- * An object A is following an object B if A and B are in the same tree
- * and A comes after B in tree order.
- *
- * * `O(n)` (worst case) where `n` is the amount of objects in the entire tree
- * * `O(1)` (amortized when walking the entire tree)
- *
- * @method following
- * @memberOf module:symbol-tree#
- * @param {!Object} object
- * @param {Object} [options]
- * @param {Object} [options.root] If set, `root` must be an inclusive ancestor
- * of the return value (or else null is returned). This check _assumes_
- * that `root` is also an inclusive ancestor of the given `object`
- * @param {Boolean} [options.skipChildren=false] If set, ignore the children of `object`
- * @return {?Object}
- */
- following(object, options) {
- const treeRoot = options && options.root;
- const skipChildren = options && options.skipChildren;
- const firstChild = !skipChildren && this._node(object).firstChild;
- if (firstChild) {
- return firstChild;
- }
- let current = object;
- do {
- if (current === treeRoot) {
- return null;
- }
- const nextSibling = this._node(current).nextSibling;
- if (nextSibling) {
- return nextSibling;
- }
- current = this._node(current).parent;
- } while (current);
- return null;
- }
- /**
- * Append all children of the given object to an array.
- *
- * * `O(n)` where `n` is the amount of children of the given `parent`
- *
- * @method childrenToArray
- * @memberOf module:symbol-tree#
- * @param {Object} parent
- * @param {Object} [options]
- * @param {Object[]} [options.array=[]]
- * @param {Function} [options.filter] Function to test each object before it is added to the array.
- * Invoked with arguments (object). Should return `true` if an object
- * is to be included.
- * @param {*} [options.thisArg] Value to use as `this` when executing `filter`.
- * @return {Object[]}
- */
- childrenToArray(parent, options) {
- const array = (options && options.array) || [];
- const filter = (options && options.filter) || returnTrue;
- const thisArg = (options && options.thisArg) || undefined;
- const parentNode = this._node(parent);
- let object = parentNode.firstChild;
- let index = 0;
- while (object) {
- const node = this._node(object);
- node.setCachedIndex(parentNode, index);
- if (filter.call(thisArg, object)) {
- array.push(object);
- }
- object = node.nextSibling;
- ++index;
- }
- return array;
- }
- /**
- * Append all inclusive ancestors of the given object to an array.
- *
- * * `O(n)` where `n` is the amount of ancestors of the given `object`
- *
- * @method ancestorsToArray
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @param {Object} [options]
- * @param {Object[]} [options.array=[]]
- * @param {Function} [options.filter] Function to test each object before it is added to the array.
- * Invoked with arguments (object). Should return `true` if an object
- * is to be included.
- * @param {*} [options.thisArg] Value to use as `this` when executing `filter`.
- * @return {Object[]}
- */
- ancestorsToArray(object, options) {
- const array = (options && options.array) || [];
- const filter = (options && options.filter) || returnTrue;
- const thisArg = (options && options.thisArg) || undefined;
- let ancestor = object;
- while (ancestor) {
- if (filter.call(thisArg, ancestor)) {
- array.push(ancestor);
- }
- ancestor = this._node(ancestor).parent;
- }
- return array;
- }
- /**
- * Append all descendants of the given object to an array (in tree order).
- *
- * * `O(n)` where `n` is the amount of objects in the sub-tree of the given `object`
- *
- * @method treeToArray
- * @memberOf module:symbol-tree#
- * @param {Object} root
- * @param {Object} [options]
- * @param {Object[]} [options.array=[]]
- * @param {Function} [options.filter] Function to test each object before it is added to the array.
- * Invoked with arguments (object). Should return `true` if an object
- * is to be included.
- * @param {*} [options.thisArg] Value to use as `this` when executing `filter`.
- * @return {Object[]}
- */
- treeToArray(root, options) {
- const array = (options && options.array) || [];
- const filter = (options && options.filter) || returnTrue;
- const thisArg = (options && options.thisArg) || undefined;
- let object = root;
- while (object) {
- if (filter.call(thisArg, object)) {
- array.push(object);
- }
- object = this.following(object, {root: root});
- }
- return array;
- }
- /**
- * Iterate over all children of the given object
- *
- * * `O(1)` for a single iteration
- *
- * @method childrenIterator
- * @memberOf module:symbol-tree#
- * @param {Object} parent
- * @param {Object} [options]
- * @param {Boolean} [options.reverse=false]
- * @return {Object} An iterable iterator (ES6)
- */
- childrenIterator(parent, options) {
- const reverse = options && options.reverse;
- const parentNode = this._node(parent);
- return new TreeIterator(
- this,
- parent,
- reverse ? parentNode.lastChild : parentNode.firstChild,
- reverse ? TreeIterator.PREV : TreeIterator.NEXT
- );
- }
- /**
- * Iterate over all the previous siblings of the given object. (in reverse tree order)
- *
- * * `O(1)` for a single iteration
- *
- * @method previousSiblingsIterator
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object} An iterable iterator (ES6)
- */
- previousSiblingsIterator(object) {
- return new TreeIterator(
- this,
- object,
- this._node(object).previousSibling,
- TreeIterator.PREV
- );
- }
- /**
- * Iterate over all the next siblings of the given object. (in tree order)
- *
- * * `O(1)` for a single iteration
- *
- * @method nextSiblingsIterator
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object} An iterable iterator (ES6)
- */
- nextSiblingsIterator(object) {
- return new TreeIterator(
- this,
- object,
- this._node(object).nextSibling,
- TreeIterator.NEXT
- );
- }
- /**
- * Iterate over all inclusive ancestors of the given object
- *
- * * `O(1)` for a single iteration
- *
- * @method ancestorsIterator
- * @memberOf module:symbol-tree#
- * @param {Object} object
- * @return {Object} An iterable iterator (ES6)
- */
- ancestorsIterator(object) {
- return new TreeIterator(
- this,
- object,
- object,
- TreeIterator.PARENT
- );
- }
- /**
- * Iterate over all descendants of the given object (in tree order).
- *
- * Where `n` is the amount of objects in the sub-tree of the given `root`:
- *
- * * `O(n)` (worst case for a single iteration)
- * * `O(n)` (amortized, when completing the iterator)
- *
- * @method treeIterator
- * @memberOf module:symbol-tree#
- * @param {Object} root
- * @param {Object} options
- * @param {Boolean} [options.reverse=false]
- * @return {Object} An iterable iterator (ES6)
- */
- treeIterator(root, options) {
- const reverse = options && options.reverse;
- return new TreeIterator(
- this,
- root,
- reverse ? this.lastInclusiveDescendant(root) : root,
- reverse ? TreeIterator.PRECEDING : TreeIterator.FOLLOWING
- );
- }
- /**
- * Find the index of the given object (the number of preceding siblings).
- *
- * * `O(n)` where `n` is the amount of preceding siblings
- * * `O(1)` (amortized, if the tree is not modified)
- *
- * @method index
- * @memberOf module:symbol-tree#
- * @param {Object} child
- * @return {Number} The number of preceding siblings, or -1 if the object has no parent
- */
- index(child) {
- const childNode = this._node(child);
- const parentNode = this._node(childNode.parent);
- if (!parentNode) {
- // In principal, you could also find out the number of preceding siblings
- // for objects that do not have a parent. This method limits itself only to
- // objects that have a parent because that lets us optimize more.
- return -1;
- }
- let currentIndex = childNode.getCachedIndex(parentNode);
- if (currentIndex >= 0) {
- return currentIndex;
- }
- currentIndex = 0;
- let object = parentNode.firstChild;
- if (parentNode.childIndexCachedUpTo) {
- const cachedUpToNode = this._node(parentNode.childIndexCachedUpTo);
- object = cachedUpToNode.nextSibling;
- currentIndex = cachedUpToNode.getCachedIndex(parentNode) + 1;
- }
- while (object) {
- const node = this._node(object);
- node.setCachedIndex(parentNode, currentIndex);
- if (object === child) {
- break;
- }
- ++currentIndex;
- object = node.nextSibling;
- }
- parentNode.childIndexCachedUpTo = child;
- return currentIndex;
- }
- /**
- * Calculate the number of children.
- *
- * * `O(n)` where `n` is the amount of children
- * * `O(1)` (amortized, if the tree is not modified)
- *
- * @method childrenCount
- * @memberOf module:symbol-tree#
- * @param {Object} parent
- * @return {Number}
- */
- childrenCount(parent) {
- const parentNode = this._node(parent);
- if (!parentNode.lastChild) {
- return 0;
- }
- return this.index(parentNode.lastChild) + 1;
- }
- /**
- * Compare the position of an object relative to another object. A bit set is returned:
- *
- * <ul>
- * <li>DISCONNECTED : 1</li>
- * <li>PRECEDING : 2</li>
- * <li>FOLLOWING : 4</li>
- * <li>CONTAINS : 8</li>
- * <li>CONTAINED_BY : 16</li>
- * </ul>
- *
- * The semantics are the same as compareDocumentPosition in DOM, with the exception that
- * DISCONNECTED never occurs with any other bit.
- *
- * where `n` and `m` are the amount of ancestors of `left` and `right`;
- * where `o` is the amount of children of the lowest common ancestor of `left` and `right`:
- *
- * * `O(n + m + o)` (worst case)
- * * `O(n + m)` (amortized, if the tree is not modified)
- *
- * @method compareTreePosition
- * @memberOf module:symbol-tree#
- * @param {Object} left
- * @param {Object} right
- * @return {Number}
- */
- compareTreePosition(left, right) {
- // In DOM terms:
- // left = reference / context object
- // right = other
- if (left === right) {
- return 0;
- }
- /* jshint -W016 */
- const leftAncestors = []; { // inclusive
- let leftAncestor = left;
- while (leftAncestor) {
- if (leftAncestor === right) {
- return TreePosition.CONTAINS | TreePosition.PRECEDING;
- // other is ancestor of reference
- }
- leftAncestors.push(leftAncestor);
- leftAncestor = this.parent(leftAncestor);
- }
- }
- const rightAncestors = []; {
- let rightAncestor = right;
- while (rightAncestor) {
- if (rightAncestor === left) {
- return TreePosition.CONTAINED_BY | TreePosition.FOLLOWING;
- }
- rightAncestors.push(rightAncestor);
- rightAncestor = this.parent(rightAncestor);
- }
- }
- const root = reverseArrayIndex(leftAncestors, 0);
- if (!root || root !== reverseArrayIndex(rightAncestors, 0)) {
- // note: unlike DOM, preceding / following is not set here
- return TreePosition.DISCONNECTED;
- }
- // find the lowest common ancestor
- let commonAncestorIndex = 0;
- const ancestorsMinLength = Math.min(leftAncestors.length, rightAncestors.length);
- for (let i = 0; i < ancestorsMinLength; ++i) {
- const leftAncestor = reverseArrayIndex(leftAncestors, i);
- const rightAncestor = reverseArrayIndex(rightAncestors, i);
- if (leftAncestor !== rightAncestor) {
- break;
- }
- commonAncestorIndex = i;
- }
- // indexes within the common ancestor
- const leftIndex = this.index(reverseArrayIndex(leftAncestors, commonAncestorIndex + 1));
- const rightIndex = this.index(reverseArrayIndex(rightAncestors, commonAncestorIndex + 1));
- return rightIndex < leftIndex
- ? TreePosition.PRECEDING
- : TreePosition.FOLLOWING;
- }
- /**
- * Remove the object from this tree.
- * Has no effect if already removed.
- *
- * * `O(1)`
- *
- * @method remove
- * @memberOf module:symbol-tree#
- * @param {Object} removeObject
- * @return {Object} removeObject
- */
- remove(removeObject) {
- const removeNode = this._node(removeObject);
- const parentNode = this._node(removeNode.parent);
- const prevNode = this._node(removeNode.previousSibling);
- const nextNode = this._node(removeNode.nextSibling);
- if (parentNode) {
- if (parentNode.firstChild === removeObject) {
- parentNode.firstChild = removeNode.nextSibling;
- }
- if (parentNode.lastChild === removeObject) {
- parentNode.lastChild = removeNode.previousSibling;
- }
- }
- if (prevNode) {
- prevNode.nextSibling = removeNode.nextSibling;
- }
- if (nextNode) {
- nextNode.previousSibling = removeNode.previousSibling;
- }
- removeNode.parent = null;
- removeNode.previousSibling = null;
- removeNode.nextSibling = null;
- removeNode.cachedIndex = -1;
- removeNode.cachedIndexVersion = NaN;
- if (parentNode) {
- parentNode.childrenChanged();
- }
- return removeObject;
- }
- /**
- * Insert the given object before the reference object.
- * `newObject` is now the previous sibling of `referenceObject`.
- *
- * * `O(1)`
- *
- * @method insertBefore
- * @memberOf module:symbol-tree#
- * @param {Object} referenceObject
- * @param {Object} newObject
- * @throws {Error} If the newObject is already present in this SymbolTree
- * @return {Object} newObject
- */
- insertBefore(referenceObject, newObject) {
- const referenceNode = this._node(referenceObject);
- const prevNode = this._node(referenceNode.previousSibling);
- const newNode = this._node(newObject);
- const parentNode = this._node(referenceNode.parent);
- if (newNode.isAttached) {
- throw Error('Given object is already present in this SymbolTree, remove it first');
- }
- newNode.parent = referenceNode.parent;
- newNode.previousSibling = referenceNode.previousSibling;
- newNode.nextSibling = referenceObject;
- referenceNode.previousSibling = newObject;
- if (prevNode) {
- prevNode.nextSibling = newObject;
- }
- if (parentNode && parentNode.firstChild === referenceObject) {
- parentNode.firstChild = newObject;
- }
- if (parentNode) {
- parentNode.childrenChanged();
- }
- return newObject;
- }
- /**
- * Insert the given object after the reference object.
- * `newObject` is now the next sibling of `referenceObject`.
- *
- * * `O(1)`
- *
- * @method insertAfter
- * @memberOf module:symbol-tree#
- * @param {Object} referenceObject
- * @param {Object} newObject
- * @throws {Error} If the newObject is already present in this SymbolTree
- * @return {Object} newObject
- */
- insertAfter(referenceObject, newObject) {
- const referenceNode = this._node(referenceObject);
- const nextNode = this._node(referenceNode.nextSibling);
- const newNode = this._node(newObject);
- const parentNode = this._node(referenceNode.parent);
- if (newNode.isAttached) {
- throw Error('Given object is already present in this SymbolTree, remove it first');
- }
- newNode.parent = referenceNode.parent;
- newNode.previousSibling = referenceObject;
- newNode.nextSibling = referenceNode.nextSibling;
- referenceNode.nextSibling = newObject;
- if (nextNode) {
- nextNode.previousSibling = newObject;
- }
- if (parentNode && parentNode.lastChild === referenceObject) {
- parentNode.lastChild = newObject;
- }
- if (parentNode) {
- parentNode.childrenChanged();
- }
- return newObject;
- }
- /**
- * Insert the given object as the first child of the given reference object.
- * `newObject` is now the first child of `referenceObject`.
- *
- * * `O(1)`
- *
- * @method prependChild
- * @memberOf module:symbol-tree#
- * @param {Object} referenceObject
- * @param {Object} newObject
- * @throws {Error} If the newObject is already present in this SymbolTree
- * @return {Object} newObject
- */
- prependChild(referenceObject, newObject) {
- const referenceNode = this._node(referenceObject);
- const newNode = this._node(newObject);
- if (newNode.isAttached) {
- throw Error('Given object is already present in this SymbolTree, remove it first');
- }
- if (referenceNode.hasChildren) {
- this.insertBefore(referenceNode.firstChild, newObject);
- }
- else {
- newNode.parent = referenceObject;
- referenceNode.firstChild = newObject;
- referenceNode.lastChild = newObject;
- referenceNode.childrenChanged();
- }
- return newObject;
- }
- /**
- * Insert the given object as the last child of the given reference object.
- * `newObject` is now the last child of `referenceObject`.
- *
- * * `O(1)`
- *
- * @method appendChild
- * @memberOf module:symbol-tree#
- * @param {Object} referenceObject
- * @param {Object} newObject
- * @throws {Error} If the newObject is already present in this SymbolTree
- * @return {Object} newObject
- */
- appendChild(referenceObject, newObject) {
- const referenceNode = this._node(referenceObject);
- const newNode = this._node(newObject);
- if (newNode.isAttached) {
- throw Error('Given object is already present in this SymbolTree, remove it first');
- }
- if (referenceNode.hasChildren) {
- this.insertAfter(referenceNode.lastChild, newObject);
- }
- else {
- newNode.parent = referenceObject;
- referenceNode.firstChild = newObject;
- referenceNode.lastChild = newObject;
- referenceNode.childrenChanged();
- }
- return newObject;
- }
- }
- module.exports = SymbolTree;
- SymbolTree.TreePosition = TreePosition;
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