Created
January 29, 2019 16:16
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JS: Tree Implementation
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| function Node(data) { | |
| this.data = data; | |
| this.parent = null; | |
| this.children = []; | |
| } | |
| function Tree(data) { | |
| this._root = new Node(data); | |
| } | |
| Tree.prototype.traverseDF = function(cb) { | |
| (function recurse(current) { | |
| for(var i = 0; i < current.children.length; i++) { | |
| recurse(current.children[i]); | |
| } | |
| cb(current); | |
| })(this._root) | |
| }; | |
| Tree.prototype.traverseBF = function(cb) { | |
| var queue = []; | |
| queue.push(this._root); | |
| current = queue.shift(); | |
| while(current) { | |
| for(var i = 0; i < current.children.length; i++) { | |
| queue.push(current.children[i]); | |
| } | |
| cb(current); | |
| current = queue.shift(); | |
| } | |
| }; | |
| Tree.prototype.contains = function(callback, traversal) { | |
| traversal.call(this, callback); | |
| }; | |
| Tree.prototype.add = function(data, toData, traversal) { | |
| var child = new Node(data), | |
| parent = null, | |
| callback = function(node) { | |
| if (node.data === toData) { | |
| parent = node; | |
| } | |
| }; | |
| this.contains(callback, traversal); | |
| if (parent) { | |
| parent.children.push(child); | |
| child.parent = parent; | |
| } else { | |
| throw new Error('Cannot add node to a non-existent parent.'); | |
| } | |
| }; | |
| Tree.prototype.remove = function(data, fromData, traversal) { | |
| var tree = this, | |
| parent = null, | |
| childToRemove = null, | |
| index; | |
| var callback = function(node) { | |
| if (node.data === fromData) { | |
| parent = node; | |
| } | |
| }; | |
| this.contains(callback, traversal); | |
| if (parent) { | |
| index = parent.children.indexOf(data); | |
| if (index === undefined) { | |
| throw new Error('Node to remove does not exist.'); | |
| } else { | |
| childToRemove = parent.children.splice(index, 1); | |
| } | |
| } else { | |
| throw new Error('Parent does not exist.'); | |
| } | |
| return childToRemove; | |
| }; | |
| var tree = new Tree('one'); | |
| tree._root.children.push(new Node('two')); | |
| tree._root.children[0].parent = tree; | |
| tree._root.children.push(new Node('three')); | |
| tree._root.children[1].parent = tree; | |
| tree._root.children.push(new Node('four')); | |
| tree._root.children[2].parent = tree; | |
| tree._root.children[0].children.push(new Node('five')); | |
| tree._root.children[0].children[0].parent = tree._root.children[0]; | |
| tree._root.children[0].children.push(new Node('six')); | |
| tree._root.children[0].children[1].parent = tree._root.children[0]; | |
| tree._root.children[2].children.push(new Node('seven')); | |
| tree._root.children[2].children[0].parent = tree._root.children[2]; | |
| /* | |
| creates this tree | |
| one | |
| ├── two | |
| │ ├── five | |
| │ └── six | |
| ├── three | |
| └── four | |
| └── seven | |
| */ | |
| // tree.traverseDF(it => console.log(it.data)); | |
| // tree.traverseBF(it => console.log(it.data)); | |
| // console.dir(tree); |
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