Package Exports

mingo

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Readme

Mingo

A JavaScript implementation of mongo-esque query language

Dependencies

underscore

Features

Simple Comparisons ($gt, $gte, $lt, $lte, $regex, $mod, $ne, $nin, $in, $all, $not)
Full conjunction support ($and, $or, $nor)
Aggregation Pipeline Support ($group, $match, $project, $sort, $limit, $unwind)
Aggregation Operators ($add, $subtract, $divide, $multiply, $cmp, $strcasecmp, $concat, $substr, $toLower, $toUpper)
Group Operators ($addToSet, $sum, $max, $min, $avg, $push, $first, $last)

Installing

$ npm install mingo

Usage

var Mingo = require('mingo');

// 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 }
});

/**
var collection = [
    { "_id" : { "$oid" : "50906d7fa3c412bb040eb577" }, "student_id" : 0, "type" : "exam", "score" : 54.6535436362647 },
    { "_id" : { "$oid" : "50906d7fa3c412bb040eb578" }, "student_id" : 0, "type" : "quiz", "score" : 31.95004496742112 },
    { "_id" : { "$oid" : "50906d7fa3c412bb040eb579" }, "student_id" : 0, "type" : "homework", "score" : 14.8504576811645 }
    ...
*/

Searching and Filtering

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

// 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();

// Removing 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}}
);

Backbone Integration

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

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);

// print grade with the lowest score
cursor.first();

Sample collection is an extract from course files from 10gen Education