lackofbrilliance / mingo

JavaScript implementation of MongoDB query language

Mingo

JavaScript implementation of MongoDB query language

Mingo harnesses the power of MongoDB-style queries and allows direct querying of in-memory javascript objects in both client and server-side environments. This library is self-contained and has zero-dependencies

Installing

$ npm install mingo

In browser

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

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
• Support integrating with custom collections via mixin
• Query filter and projection streaming. See mingo-stream

For documentation on using query operators see mongodb

Usage

var Mingo = require('mingo');
// or just access *Mingo* global in browser

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

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

Searching and Filtering

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

// filter collection with find()
var 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 (
var result = query.remove(collection);

Aggregation Pipeline

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

var 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)
var Grades = Backbone.Collection.extend(Mingo.CollectionMixin);

// `collection` is an array of objects
var 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

Contributing

• Submit pull requests to the development branch

License

MIT