https://github.com/latentflip/level-tree-db

A leveldb backed tree structure.
https://github.com/latentflip/level-tree-db

Last synced: 30 days ago
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A leveldb backed tree structure.

• Host: GitHub
• URL: https://github.com/latentflip/level-tree-db
• Owner: latentflip
• Created: 2014-01-14T11:02:29.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2014-01-26T20:18:08.000Z (almost 11 years ago)
• Last Synced: 2024-04-15T02:17:46.734Z (7 months ago)
• Language: JavaScript
• Size: 180 KB
• Stars: 1
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# level-tree-db (could probably have a better name)

A generic tree backed by level db.

## Example

### Create a Tree, Insert some elements, breadth-first walk the tree

```javascript

var level = require('level');

var leveldown = require('leveldown');

var Tree = require('./tree');

var dbPath = './trees.db';

leveldown.destroy(dbPath, function () {

    var db = level(dbPath, { valueEncoding: 'json' });

    //db: the leveldb database to save to

    //treeId: identifier of the tree to save/load

    var tree = new Tree({ db: db, treeId: 'myTree' });

    //Insert a node with some data

    //tree.insertNode(parentNodeId, nodeData, cb(err, nodeId));

    tree.insertNode(tree.rootId, { name: 'Node A' }, function (err, nodeAId) {

        if (err) throw err;

        //Add { name: 'Node B' } to the root

        tree.insertNode(tree.rootId, { name: 'Node B' }, function (err, nodeBId) {

            //Add { name: 'Node C' } to node A

            tree.insertNode(nodeBId, { name: 'Node C' }, function (err, nodeCId) {

                //Breadth first traverse the tree from the root

                tree.breadthWalk(function (nodeId, children, data) {

                    console.log('Node', nodeId, 'has data', data, 'and children', children);

                }, function (err) {

                    if (err) throw err;

                    console.log('Done walking');

                });

            });

        });

    });

});

```

outputs:

```

Node myTree/root has data {} and children [ 'myTree/node-f9851923-15a6-418c-898b-9af6a96fd732',

  'myTree/node-fa37a40c-405b-458b-a302-55adf44083a2' ]

Node myTree/node-f9851923-15a6-418c-898b-9af6a96fd732 has data { name: 'Node A' } and children []

Node myTree/node-fa37a40c-405b-458b-a302-55adf44083a2 has data { name: 'Node B' } and children [ 'myTree/node-b8a48562-7431-49cf-8f58-60207d84606b' ]

Node myTree/node-b8a48562-7431-49cf-8f58-60207d84606b has data { name: 'Node C' } and children []

Done walking

```