mingo

What is mingo?

Mingo is a JavaScript library that provides MongoDB-like query and aggregation capabilities for in-memory data processing. It allows you to filter, sort, group, and transform data collections using a syntax similar to MongoDB queries.

What are mingo's main functionalities?

Querying

This feature allows you to perform complex queries on your data collections. The example demonstrates how to filter a list of people to find those older than 26.

const mingo = require('mingo');
const data = [
  { name: 'John', age: 25 },
  { name: 'Jane', age: 30 },
  { name: 'Jim', age: 27 }
];
const query = new mingo.Query({ age: { $gt: 26 } });
const result = query.find(data).all();
console.log(result); // Output: [ { name: 'Jane', age: 30 }, { name: 'Jim', age: 27 } ]

Aggregation

This feature allows you to perform aggregation operations on your data collections. The example demonstrates how to calculate the average salary of people older than 26.

const mingo = require('mingo');
const data = [
  { name: 'John', age: 25, salary: 50000 },
  { name: 'Jane', age: 30, salary: 60000 },
  { name: 'Jim', age: 27, salary: 55000 }
];
const pipeline = [
  { $match: { age: { $gt: 26 } } },
  { $group: { _id: null, averageSalary: { $avg: '$salary' } } }
];
const result = mingo.aggregate(data, pipeline);
console.log(result); // Output: [ { _id: null, averageSalary: 57500 } ]

Projection

This feature allows you to project specific fields from your data collections. The example demonstrates how to retrieve only the 'name' and 'age' fields from a list of people.

const mingo = require('mingo');
const data = [
  { name: 'John', age: 25, salary: 50000 },
  { name: 'Jane', age: 30, salary: 60000 },
  { name: 'Jim', age: 27, salary: 55000 }
];
const query = new mingo.Query({});
const result = query.find(data).project({ name: 1, age: 1 }).all();
console.log(result); // Output: [ { name: 'John', age: 25 }, { name: 'Jane', age: 30 }, { name: 'Jim', age: 27 } ]

Other packages similar to mingo

lodash

Lodash is a JavaScript utility library that provides a wide range of functions for manipulating arrays, objects, and other data structures. While it does not offer MongoDB-like query syntax, it provides similar functionalities for filtering, sorting, and transforming data collections.

underscore

Underscore is another JavaScript utility library similar to Lodash. It provides a set of utility functions for working with arrays, objects, and other data types. Like Lodash, it does not offer MongoDB-like query syntax but provides similar data manipulation capabilities.

json-query

json-query is a library for querying JSON data structures using a simple query language. It provides functionalities for filtering and transforming JSON data, similar to Mingo, but with a different query syntax.

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