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https://github.com/shimohq/ioredis-tree
🌲 A robust tree structure implementation for Redis
https://github.com/shimohq/ioredis-tree
ioredis redis tree
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🌲 A robust tree structure implementation for Redis
- Host: GitHub
- URL: https://github.com/shimohq/ioredis-tree
- Owner: shimohq
- License: mit
- Created: 2015-11-13T05:52:05.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2023-04-16T20:49:07.000Z (over 1 year ago)
- Last Synced: 2024-09-18T06:52:42.687Z (3 months ago)
- Topics: ioredis, redis, tree
- Language: JavaScript
- Homepage:
- Size: 77.1 KB
- Stars: 85
- Watchers: 16
- Forks: 12
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ioredis-tree
A robust tree structure implementation for Redis
[](https://travis-ci.org/shimohq/ioredis-tree)
[](https://david-dm.org/shimohq/ioredis-tree)
## Install
```shell
npm install ioredis-tree
```
## Usage
```javascript
var Redis = require('ioredis');
var redis = require('ioredis-tree')(new Redis());
redis.tinsert('files', 'parent', 'node');
```
## NOTE
Starting from v1.0.0, ioredis-tree assumes that nodes containing char ':' are the root of the tree for performance reasons.
## API
### TINSERT key parent node
Insert `node` to `parent`. If `parent` does not exist, a new tree with root of `parent` is created.
#### Example
```javascript
redis.tinsert('mytree', '1', '2');
```
Creates:
```
+-----+
| 1 |
+----+-----+
|
+--+--+
| 2 |
+-----+
```
```javascript
redis.tinsert('mytree', '1', '4');
```
Creates:
```
+-----+
| 1 |
+----+-----+----+
| |
+--+--+ +--+--+
| 2 | | 4 |
+-----+ +-----+
```
`TINSERT` accepts one of the three optional options to specified where to insert the node into:
1. `INDEX`: Insert the node to the specified index. Index starts with `0`, and it can also be negative numbers indicating offsets starting at the end of the list. For example, `-1` is the last element of the list, `-2` the penultimate, and so on. If the index is out of the range, the node will insert into the tail (when positive) or head (when negative).
2. `BEFORE`: Insert the node before the specified node. Insert to the head when the specified node is not found.
3. `AFTER`: Insert the node after the specified node. Insert to the tail when the specified node is not found.
Continue with our example:
```javascript
redis.tinsert('mytree', '1', '3', { before: '4' });
// Or:
// redis.tinsert('mytree', '1', '3', { after: '2' });
// redis.tinsert('mytree', '1', '3', { index: 1 });
// redis.tinsert('mytree', '1', '3', { index: -2 });
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| | |
+--+--+ +--+--+ +--+--+
| 2 | | 3 | | 4 |
+-----+ +-----+ +-----+
```
```javascript
redis.tinsert('mytree', '2', '5', { index: 1000 });
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| | |
+--+--+ +--+--+ +--+--+
| 2 | | 3 | | 4 |
+--+--+ +-----+ +-----+
|
+--+--+
| 5 |
+-----+
```
A node can have multiple parents, say we insert `4` into `5`:
```javascript
redis.tinsert('mytree', '5', '4');
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| | |
+--+--+ +--+--+ +--+--+
| 2 | | 3 | | 4 |
+--+--+ +-----+ +-----+
|
+--+--+
| 5 |
+--+--+
|
+--+--+
| 4 |
+-----+
```
It's not allowed to move a node into its posterity, which will lead an error:
```javascript
redis.tinsert('mytree', '3', '1');
// ERR parent node cannot be the posterity of new node
```
### TPARENTS key node
Get the parents of the node. Returns an empty array when doesn't have parent.
```javascript
redis.tparents('mytree', '5'); // ['2']
redis.tparents('mytree', '1'); // []
redis.tparents('mytree', '4'); // ['5', '1']
redis.tparents('non-exists tree', '1'); // []
redis.tparents('mytree', 'non-exists node'); // []
```
The order of parents is random.
### TPATH key from to
Get the path between `from` and `to`. The depth of `from` must lower than `to`. Return `null` if `from` isn't a ancestor of `to`.
```javascript
redis.tpath('mytree', '1', '5'); // ['2']
redis.tpath('mytree', '1', '3'); // []
redis.tpath('mytree', '1', '7'); // null
```
If there's more than one path between the two nodes, the shorter path will be returned:
```javascript
redis.tpath('mytree', '1', '4'); // []
```
### TCHILDREN key node
Get the children of the node. Each node has at least two properties:
1. `node`: The node itself.
2. `hasChild`: `true` or `false`, whether the node has at least one child.
If the `hasChild` is `true`, there will be an additional `children` property, which is an array containing the children of the node.
```javascript
redis.tchildren('mytree', '1');
// [
// { node: '2', hasChild: true, children: [{ node: '5', hasChild: false }] },
// { node: '3', hasChild: false },
// { node: '4', hasChild: false }
// ]
redis.tchildren('mytree', '5'); // []
redis.tchildren('non-exists tree', '1'); // []
redis.tchildren('mytree', 'non-exists node'); // []
```
`TCHILDREN` accepts a `LEVEL` option to specified how many levels of children to fetch:
```javascript
redis.tchildren('mytree', '1', { level: 1 });
// [
// { node: '2', hasChild: true },
// { node: '3', hasChild: false },
// { node: '4', hasChild: false }
// ]
```
Notice that although node '2' has a child (its `hasChild` is `true`), it doesn't has the `children` property since we are only insterested in the first level children by specifying `{ level: 1 }`.
### TREM key parent count node
Remove the reference of a node from a parent.
```javascript
redis.trem('mytree', '5', 0, '4');
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| | |
+--+--+ +--+--+ +--+--+
| 2 | | 3 | | 4 |
+--+--+ +-----+ +-----+
|
+--+--+
| 5 |
+-----+
```
The `count` argument influences the operation in the following ways:
* count > 0: Remove nodes moving from head to tail.
* count < 0: Remove nodes moving from tail to head.
* count = 0: Remove all nodes.
`TREM` returns the remaining nodes in the parent.
### TMREM key node
Remove the node from all parents. Use `not` option to exclude a parent.
```javascript
redis.tmrem('mytree', '2', { not: '3' });
```
### TDESTROY key node
Destroy a node recursively and remove all references of it. Returns the count of nodes being deleted.
```javascript
redis.tdestroy('mytree', '2'); // returns 2, since "2" and "5" are deleted.
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| |
+--+--+ +--+--+
| 3 | | 4 |
+-----+ +-----+
```
### TMOVECHILDREN key sourceNode targetNode [APPEND|PREPEND]
Move all the children of the `sourceNode` to `targetNode`. By default the new nodes will be
appended to the target node, if `PREPEND` option is passed, the new nodes will be prepended
to the target node.
```javascript
redis.tmovechildren('mytree', 'source', 'target', 'PREPEND');
```
### TEXISTS key node
Returns if node exists.
```javascript
redis.texists('mytree', '2'); // 0
redis.texists('mytree', '1'); // 1
```
### TRENAME key node name
Rename a node.
```javascript
redis.trename('mytree', '2', '5');
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| |
+--+--+ +--+--+
| 5 | | 4 |
+-----+ +-----+
```
### TPRUNE key node
Prune a tree to remove its children from parents which don't belong to the node.
Given the following two trees:
```
+-----+
| 1 |
+----+--+--+----+
| |
+--+--+ +--+--+
| 5 | | 4 |
+-----+ +-----+
+-----+
| 6 |
+----+--+--+
|
+--+--+
| 5 |
+-----+
```
```javascript
redis.tprune('mytree', '1');
```
Creates:
```
+-----+
| 1 |
+----+--+--+----+
| |
+--+--+ +--+--+
| 5 | | 4 |
+-----+ +-----+
+-----+
| 6 |
+--+--+
```
## Cluster Compatibility
This module supports Redis Cluster by ensuring all nodes that are belong to a tree have a same slot.
## Performance
Benefiting from the high performance of Redis, modifying a tree is very fast. For instance, getting all children of a tree with the level of 100 recursively in a iMac 5k costs 4ms.