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

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,$$KEEP,$$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

• API
• Custom Operators

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

• Squash changes into one commit
• Run make to ensure tests pass
• Submit pull request

License

MIT