mingo

JavaScript implementation of MongoDB query language

Install

$ npm install mingo

Features

Supports Dot Notation for both <array>.<index> and <document>.<field> selectors
Query and Projection Operators
Aggregation Framework Operators
Support for adding custom operators
Match against user-defined types
Support for aggregaion variables
- $$ROOT,$$CURRENT,$$DESCEND,$$PRUNE,$$KEEP,$$REMOVE
ES6 module compatible
Support integrating with custom collections via mixin
Query filter and projection streaming.

For documentation on using query operators see mongodb

Documentation

Usage

On the server side

// Use as es6 module
import mingo from 'mingo'

// or vanilla nodeJS
var mingo = require('mingo')

For the browser

// minified UMD module
<script type="text/javascript" src="./dist/mingo.min.js"></script>

// or gzipped UMD module
<script type="text/javascript" src="./dist/mingo.min.js.gz"></script>

Tiny configuration if needed

// setup the key field for your collection
mingo.setup({
    key: '_id' // default
});

Using query object to test objects

// create a query with criteria
// find all grades for homework with score >= 50
let query = new mingo.Query({
    type: "homework",
    score: { $gte: 50 }
});

// test if an object matches query
query.test(someObject)

Searching and Filtering

// input is either an Array or any iterable source (i.e Object{next:Function}) including ES6 generators.

// filter collection with find()
let cursor = query.find(collection)

// shorthand with query criteria
cursor = mingo.find(collection, criteria)

// sort, skip and limit by chaining
cursor.sort({student_id: 1, score: -1})
    .skip(100)
    .limit(100)

// count matches. exhausts cursor
cursor.count()

// classic cursor iterator (old school)
while (cursor.hasNext()) {
    console.log(cursor.next())
}

// ES6 iterators (new cool)
for (let value of cursor) {
  console.log(value)
}

// all() to retrieve matched objects. exhausts cursor
cursor.all()

Aggregation Pipeline

let agg = new mingo.Aggregator([
    {'$match': { "type": "homework"}},
    {'$group':{'_id':'$student_id', 'score':{$min:'$score'}}},
    {'$sort':{'_id': 1, 'score': 1}}
])

// return an iterator for streaming results
let stream = agg.stream(collection)

// return all results. same as `stream.all()`
let result = agg.run(collection)

Integration with custom collection

// using Backbone.Collection as an example (any user-defined object will do)
let Grades = Backbone.Collection.extend(mingo.CollectionMixin)

// `collection` is an array of objects
let grades = new Grades(collection)

// find students with grades less than 50 in homework or quiz
// sort by score ascending and type descending
cursor = grades.query({
  $or: [{type: "quiz", score: {$lt: 50}}, {type: "homework", score: {$lt: 50}}]
}).sort({score: 1, type: -1}).limit(10)

// return grade with the lowest score
cursor.next()

The collection to mixin needs to provide a method with signature toJSON() -> Array[Object].

Why?

Alternative to writing lots of custom code for transforming collection of objects
Quick validation of MongoDB queries without the need for a database
MongoDB query language is among the best in the market and is well documented

Contributing

Submit pull requests to the development branch
Squash changes into one commit
Run make to ensure tests pass

License

MIT

unwriter/mingo