A fully persistent balanced binary search tree
npm install functional-red-black-treefunctional-red-black-tree
=========================
A fully persistent red-black tree written 100% in JavaScript. Works both in node.js and in the browser via browserify.
Functional (or fully presistent) data structures allow for non-destructive updates. So if you insert an element into the tree, it returns a new tree with the inserted element rather than destructively updating the existing tree in place. Doing this requires using extra memory, and if one were naive it could cost as much as reallocating the entire tree. Instead, this data structure saves some memory by recycling references to previously allocated subtrees. This requires using only O(log(n)) additional memory per update instead of a full O(n) copy.
Some advantages of this is that it is possible to apply insertions and removals to the tree while still iterating over previous versions of the tree. Functional and persistent data structures can also be useful in many geometric algorithms like point location within triangulations or ray queries, and can be used to analyze the history of executing various algorithms. This added power though comes at a cost, since it is generally a bit slower to use a functional data structure than an imperative version. However, if your application needs this behavior then you may consider using this module.
npm install functional-red-black-tree
Here is an example of some basic usage:
``javascript
//Load the library
var createTree = require("functional-red-black-tree")
//Create a tree
var t1 = createTree()
//Insert some items into the tree
var t2 = t1.insert(1, "foo")
var t3 = t2.insert(2, "bar")
//Remove something
var t4 = t3.remove(1)
`
`javascript`
var createTree = require("functional-red-black-tree")
- Tree methods
- [var tree = createTree([compare])](#var-tree-=-createtreecompare)tree.keys
- tree.values
- tree.length
- tree.get(key)
- tree.insert(key, value)
- tree.remove(key)
- tree.find(key)
- tree.ge(key)
- tree.gt(key)
- tree.lt(key)
- tree.le(key)
- tree.at(position)
- tree.begin
- tree.end
- tree.forEach(visitor(key,value)[, lo[, hi]])
- [](#treeforEachvisitorkeyvalue-lo-hi)tree.root
- node.key
- Node properties
- node.value
- node.left
- node.right
- iter.key
- Iterator methods
- iter.value
- iter.node
- iter.tree
- iter.index
- iter.valid
- iter.clone()
- iter.remove()
- iter.update(value)
- iter.next()
- iter.prev()
- iter.hasNext
- iter.hasPrev
-
* compare is an optional comparison function, same semantics as array.sort()
Returns An empty tree ordered by compare
* key is the key of the item to look up
Returns The value of the first node associated to key
* key is the key of the item to insertvalue
* is the value of the item to insert
Returns A new tree with key and value inserted
in the tree*
key is the key of the item to removeReturns A new tree with the given item removed if it exists
$3
Returns an iterator pointing to the first item in the tree with key, otherwise null.$3
Find the first item in the tree whose key is >= key*
key is the key to search forReturns An iterator at the given element.
$3
Finds the first item in the tree whose key is > key*
key is the key to search forReturns An iterator at the given element
$3
Finds the last item in the tree whose key is < key*
key is the key to search forReturns An iterator at the given element
$3
Finds the last item in the tree whose key is <= key*
key is the key to search forReturns An iterator at the given element
$3
Finds an iterator starting at the given element*
position is the index at which the iterator gets createdReturns An iterator starting at position
$3
An iterator pointing to the first element in the tree$3
An iterator pointing to the last element in the tree$3
Walks a visitor function over the nodes of the tree in order.*
visitor(key,value) is a callback that gets executed on each node. If a truthy value is returned from the visitor, then iteration is stopped.
* lo is an optional start of the range to visit (inclusive)
* hi is an optional end of the range to visit (non-inclusive)Returns The last value returned by the callback
$3
Returns the root node of the tree
Node properties
Each node of the tree has the following properties:$3
The key associated to the node$3
The value associated to the node$3
The left subtree of the node$3
The right subtree of the nodeIterator methods
$3
The key of the item referenced by the iterator$3
The value of the item referenced by the iterator$3
The value of the node at the iterator's current position. null is iterator is node valid.$3
The tree associated to the iterator$3
Returns the position of this iterator in the sequence.$3
Checks if the iterator is valid$3
Makes a copy of the iterator$3
Removes the item at the position of the iteratorReturns A new binary search tree with
iter`'s item removedReturns A new binary search tree with the corresponding node updated