A javascript implementation of red-black-tree using ES6

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* https://www.npmjs.com/package/red-black-tree-js

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`` npm i red-black-tree-js `

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`javascript
import RbTree from "red-black-tree-js"

const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");
rbTree.insert(3, "bar");
rbTree.insert(4, "bar");
rbTree.insert(5, "bar");
rbTree.insert(6, "bar");
rbTree.remove(6);

const iterator = rbTree.createIterator();

let result = [];
while (iterator.hasNext()) {
result.push(iterator.next());
}

`

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* https://www.cs.usfca.edu/~galles/visualization/RedBlack.html visualization
* https://en.wikipedia.org/wiki/Red%E2%80%93black_tree wiki

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* data structure

| nodeColor | value |
| --------- | ----- |
| BLACK | 1 |
| RED | 0 |

| Node | LeafNode |
| ---- | -------- |
| left | left(null) |
| right | right(null) |
| parent | parent(null) |
| key | key(null) |
| value | value(null) |
| color | color(black) |

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* create RB TREE
` let rbTree = new RbTree() `
create a red black tree with root = null

* find
`javascript
const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");
rbTree.insert(3, "bar");
const value = rbTree.find(2);

value is "bar"
Look up value by it's key
`
* iterator()
return the next smallest number

`javascript
rbTree.insert(30, "abc");
rbTree.insert(20, "foo");
rbTree.insert(40, "bar");
rbTree.insert(10, "bar");
const iterator = rbTree.createIterator();

let result = [];
while (iterator.hasNext()) {
result.push(iterator.next());
}

`

* findNode(key)
`javascript
const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");
rbTree.insert(3, "bar");
const node = rbTree.findNode(2);

return the node object
`

* update(key, value)
`javascript
const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");

rbTree.update(2, "updated")

now the value is "updated"
`

* insert(key, value)
`rbTree.insert(1, "abc")`
insert a key and a value to a node

* remove(key)
`rbTree.remove(1)`
remove a node by its key

* print()
`javascript
rbTree.insert(30, "abc");
rbTree.insert(20, "foo");
rbTree.insert(40, "bar");
rbTree.insert(10, "bar");
rbTree.print();

30 color: 1
___20 color: 0 (parent node 30)
___40 color: 0 (parent node 30)
______null color: 1 (parent node 20)
______null color: 1 (parent node 20)
______null color: 1 (parent node 40)
______null color: 1 (parent node 40)

`
print out the current tree in a good format

* inOrderSucc(node)
`javascript
const rbTree = new RbTree();
rbTree.insert(2, "foo");
rbTree.insert(1, "bar");
rbTree.insert(3, "bar");

let next = rbTree.inOrderSucc(rbTree.root)
console.log(next)
{key : 3, value: "bar"}

`

* toSortedArray()
`javascript
const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");
rbTree.insert(3, "bar");
const array = rbTree.toSortedArray();

array is [Object, Object, Object]
return a sorted array of objects that contains key and value
`

* toArrayPreOrder()
`javascript
const rbTree = new RbTree();
rbTree.insert(3, "abc");
rbTree.insert(4, "abc");
rbTree.insert(1, "foo");
rbTree.insert(0, "bar");
rbTree.insert(2, "bar");
const array = rbTree.toArrayPreOrder();

array is [Object, Object, Object, Object, Object]
return an array of objects that contains key and value
the key order is [3, 1, 0, 2, 4]
`

* toArrayPostOrder()
`javascript
const rbTree = new RbTree();
rbTree.insert(3, "abc");
rbTree.insert(4, "abc");
rbTree.insert(1, "foo");
rbTree.insert(0, "bar");
rbTree.insert(2, "bar");
const array = rbTree.toArrayPostOrder();

array is [Object, Object, Object, Object, Object]
the key order is [0, 2, 1, 4, 3]
return an array of objects that contains key and value
`

* minNode()
`javascript
const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");
rbTree.insert(3, "bar");
const node = rbTree.minNode();

node is Object {key: 1, value: "foo"}
return the smallest node value in the tree
`

* maxNode()
`javascript
const rbTree = new RbTree();
rbTree.insert(1, "foo");
rbTree.insert(2, "bar");
rbTree.insert(3, "bar");
const node = rbTree.maxNode();

node is Object {key: 3, value: "bar"}
return the largest node value in the tree
`




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##### For example:

letter 'a' will be treated as 1
letter 'b' will be treated as 2
letter 'b' will be treated as 3
letter 'A' will be treated as 1 as well
letter 'B' will be treated as 2 as well
letter 'C' will be treated as 3 as well
a string like "abc" will be treated as 123
a string like "Abc" will be treated as 123
a string like "dc" will be treated as 41

`javascript
rbTree.insert("id", 1001) => rbTree.insert(94, 1001);
rbTree.insert("a", "foo") => rbTree.insert(1, "foo");
rbTree.insert("Am", "bar")=> rbTree.insert(113, "foo");
rbTree.insert("boy", "foo") => rbTree.insert(21525, "foo");
``

* future work
Better print format
Pass all linter
and more ...