mongoose-tree

Implements the materialized path strategy for storing a hierarchy of documents with mongoose

Warning: the original code is from Brian Kirchoff, but it seem's that he no longer take care of mongoo-tree. https://github.com/briankircho/mongoose-tree

Usage

Install via NPM

$ npm install mongoose-tree

Then you can use the plugin on your schemas

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

getChildren

Signature:

getChildren([recursive], cb);

if recursive is supplied and true, subchildren are returned

Based on the above hierarchy:

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
});

getChildrenTree

Signature:

getChildrenTree([args], cb);

return a recursive tree of subchildren.

args is an object you can defined with theses properties :

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

columns: mongoose columns, optional, default null (all columns)
  example: columns: {"_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 childs for the specified level
  example: recursive:false

emptyChilds: boolean, default true
  if true, every childs not having subchilds will have childs attribute (empty array)
  if false, every childs not having subchilds will not have childs attribute

Example :

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

getChildren(args,myCallback);
```

Based on the above hierarchy:

adam.getChildren([function](err, users) {

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

});

getAncestors

Signature:

getAncestors(cb);

Based on the above hierarchy:

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

level

Equal to the level of the hierarchy

carol.level; // equals 3

Tests

To run the tests install mocha

npm install mocha -g

and then run

mocha