mongoose-path-tree


Implements the materialized path strategy with cascade child re-parenting on delete for storing a hierarchy of documents with mongoose
Version with all collected features and fixes from mongoose-tree, mongoose-tree-fix, mongoose-tree2, mongoose-reparenting-tree

Usage

Install via NPM

$ npm install mongoose-path-tree

Options

``javascript
Model.plugin(tree, {
pathSeparator : '#' // Default path separator
onDelete : 'REPARENT' // Can be set to 'DELETE' or 'REPARENT'. Default: 'REPARENT'
numWorkers: 5 // Number of stream workers
idType: Schema.ObjectId // Type used for _id. Can be, for example, String generated by shortid module
})
`

Then you can use the plugin on your schemas

`javascript
var tree = require('mongoose-path-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([filters], [fields], [options], [recursive], cb);

args are additional filters if needed.
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 as method:

getChildrenTree([args], cb);

Signature as static:

getChildrenTree([rootDoc], [args], cb);

return a recursive tree of sub-children.

args is an object you can defined with theses properties :

filters: mongoose query filter, optional, default null
example: filters: {owner:myId}

fields: mongoose fields, optional, default null (all fields)
example: fields: "_id name owner"

options: mongoose query option, optional, default null
example: options:{{sort:'-name'}}

minLevel: level at which will start the search, default 1
example: minLevel:2

recursive: boolean, default true
make the search recursive or only fetch children for the specified level
example: recursive:false

allowEmptyChildren: boolean, default true
if true, every child not having children will have 'children' attribute (empty array)
if false, every child not having children will not have 'children' attribute

Example :

`javascript
var args = {
filters: {owner:myId},
fields: "_id name owner",
minLevel:2,
recursive:true,
allowEmptyChildren:false
}

getChildrenTree(args,myCallback);
`

Based on the above hierarchy:

`javascript
adam.getChildrenTree( function(err, users) {

/* if you dump users, you will have something like this :
{
"_id" : ObjectId("50136e40c78c4b9403000001"),
"name" : "Adam",
"path" : "50136e40c78c4b9403000001"
"children" : [{
"_id" : ObjectId("50136e40c78c4b9403000002"),
"name" : "Bob",
"parent" : ObjectId("50136e40c78c4b9403000001"),
"path" : "50136e40c78c4b9403000001#50136e40c78c4b9403000002"
"children" : [{
"_id" : ObjectId("50136e40c78c4b9403000003"),
"name" : "Carol",
"parent" : ObjectId("50136e40c78c4b9403000002"),
"path" : "50136e40c78c4b9403000001#50136e40c78c4b9403000002#50136e40c78c4b9403000003"
}]
}]
}
*/

});

`

$3

Signature:

getAncestors([filters], [fields], [options], 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