mongoose-reparenting-tree

Implements the materialized path strategy with cascade child re-parenting on delete for storing a hierarchy of documents with mongoose

Usage

Install via NPM

$ npm install mongoose-reparenting-tree

Options

``javascript
Model.plugin(tree, {
pathSeparator : '#' // Default path separator
onDelete : 'REPARENT' // Can be set to 'DELETE' or 'REPARENT'. Default: 'REPARENT'
})
`

Then you can use the plugin on your schemas

`javascript
var tree = require('mongoose-tree');

var UserSchema = new Schema({
name : String
});
UserSchema.plugin(tree);
var User = mongoose.model('User', UserSchema);

var adam = new User({ name : 'Adam' });
var bob = new User({ name : 'Bob' });
var carol = new User({ name : 'Carol' });

// Set the parent relationships
bob.parent = adam;
carol.parent = bob;

adam.save(function() {
bob.save(function() {
carol.save();
});
});
`

At this point in mongoDB you will have documents similar to

{
"_id" : ObjectId("50136e40c78c4b9403000001"),
"name" : "Adam",
"path" : "50136e40c78c4b9403000001"
}
{
"_id" : ObjectId("50136e40c78c4b9403000002"),
"name" : "Bob",
"parent" : ObjectId("50136e40c78c4b9403000001"),
"path" : "50136e40c78c4b9403000001#50136e40c78c4b9403000002"
}
{
"_id" : ObjectId("50136e40c78c4b9403000003"),
"name" : "Carol",
"parent" : ObjectId("50136e40c78c4b9403000002"),
"path" : "50136e40c78c4b9403000001#50136e40c78c4b9403000002#50136e40c78c4b9403000003"
}

The path is used for recursive methods and is kept up to date by the plugin if the parent is changed

API

$3

Signature:

getChildren([recursive], cb);

if recursive is supplied and true subchildren are returned

Based on the above hierarchy:

`javascript
adam.getChildren(function(err, users) {
// users is an array of with the bob document
});

adam.getChildren(true, function(err, users) {
// users is an array with both bob and carol documents
});
`

$3

Signature:

getAncestors(cb);

Based on the above hierarchy:

`javascript
carol.getAncestors(function(err, users) {
// users is an array of adam and bob
})
`

$3

Equal to the level of the hierarchy

`javascript
carol.level; // equals 3
``

Tests

To run the tests install mocha

npm install mocha -g

and then run

mocha