mingo

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
  • Array Operators
  • Comparisons Operators
  • Element Operators
  • Evaluation Operators
  • Logical Operators
• Aggregation Framework Operators
  • Pipeline Operators
  • Group Operators
  • Projection Operators
  • Arithmetic Operators
  • Array Operators
  • Boolean Operators
  • Comparisons Operators
  • Conditional Operators
  • Date Operators
  • Literal Operators
  • Set Operators
  • String Operators
  • Variable Operators
• Support for adding custom operators
• Match against user-defined types
• Support for aggregaion variables
  • $$ROOT,$$CURRENT,$$DESCEND,$$PRUNE,$$KEEP
• Fully ES6 module compatible
• Support integrating with custom collections via mixin
• Query filter and projection streaming. See mingo-stream

For documentation on using query operators see mongodb

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 }
});

query.test(someObject)

Searching and Filtering

// `collection` is an Array of objects you want to query

// 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
cursor.count();

// iterate cursor
// iteration is forward only
while (cursor.hasNext()) {
    console.log(cursor.next());
}

// use first(), last() and all() to retrieve matched objects
cursor.first();
cursor.last();
cursor.all();

// Filter non-matched objects (
console.log(query.remove(collection));

Aggregation Pipeline

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

let result = agg.run(collection);

// shorthand
result = mingo.aggregate(
  collection,
  [
    {'$match': { "type": "homework"}},
    {'$group':{'_id':'$student_id', 'score':{$min:'$score'}}},
    {'$sort':{'_id': 1, 'score': 1}}
  ]
);

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.first();

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

Documentation

• API
• Custom Operators

Why?

• Born out of a real need
• Alternative to writing a lot of custom code for transforming collections of JSON 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
• Finally, because queries are better than me and perhaps you too :)

Contributing

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

License

MIT