DanneLeung/mongoose-path-tree

mongoose plugin for tree hierarchy using the materialized path strategy

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

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

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

getChildren

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:

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 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 :

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

getChildrenTree(args,myCallback);

Based on the above hierarchy:

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"
          }]
      }]
    }
    */

});

getAncestors

Signature:

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