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0.1.17 • Public • Published

diskDB Build Status NPM version Gitter


A Lightweight Disk based JSON Database with a MongoDB like API for Node.

You will never know that you are interacting with a File System


Getting Started

Install the module locally :

$ npm install diskdb
var db = require('diskdb');
db = db.connect('/path/to/db-folder', ['collection-name']);
// you can access the traditional JSON DB methods here


Connect to DB

db.connect(pathToFolder, ['filename']);

Filename will be the name of the JSON file. You can omit the extension, diskDB will take care of it for you.

var db = require('diskdb');
db = db.connect('/examples/db', ['articles']);
// or simply
db.connect('/examples/db', ['articles']);

This will check for a directory at given path, if it does not exits, diskDB will throw an error and exit.

If the directory exists but the file/collection does not exist, diskDB will create it for you.

Note : If you have manually created an empty JSON file, please make sure that it contains at least an empty array.


Else it will throw an error like

SyntaxError: Unexpected end of input

Load Collections

Alternatively you can also load collections like

var db = require('diskdb');
// this
db = db.connect('/examples/db');
db.connect('/examples/db', ['articles']);

Load Multiple Collections

var db = require('diskdb');
db.connect('/examples/db', ['articles','comments','users']);

Write/Save to Collection


Once you have loaded a collection, you can access the collection's methods using the dot notation like


To save the data, you can use

var db = require('diskdb');
db.connect('db', ['articles']);
var article = {
    title : "diskDB rocks",
    published : "today",
    rating : "5 stars"
// or

The saved data will be

        "title": "diskDB rocks",
        "published": "today",
        "rating": "5 stars",
        "_id": "0f6047c6c69149f0be0c8f5943be91be"

You can also save multiple objects at once like

var db = require('diskdb');
db.connect('db', ['articles']);
var article1 = {
    title : 'diskDB rocks',
    published : 'today',
    rating : '5 stars'
var article2 = {
    title : 'diskDB rocks',
    published : 'yesterday',
    rating : '5 stars'
var article3 = {
    title : 'diskDB rocks',
    published : 'today',
    rating : '4 stars'
db.articles.save([article1, article2, article3]);

And this will return the inserted objects

[ { title: 'diskDB rocks',
    published: 'today',
    rating: '4 stars',
    _id: 'b1cdbb3525b84e8c822fc78896d0ca7b' },
  { title: 'diskDB rocks',
    published: 'yesterday',
    rating: '5 stars',
    _id: '42997c62e1714e9f9d88bf3b87901f3b' },
  { title: 'diskDB rocks',
    published: 'today',
    rating: '5 stars',
    _id: '4ca1c1597ddc4020bc41b4418e7a568e' } ]

Read from Collection

There are 2 methods available for reading the JSON collection

  • db.collectionName.find(query)
  • db.collectionName.findOne(query)


var db = require('diskdb');
db.connect('/examples/db', ['articles']);

This will return all the records

    title: 'diskDB rocks',
    published: 'today',
    rating: '5 stars',
    _id: '0f6047c6c69149f0be0c8f5943be91be'

You can also query with a criteria like

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.find({rating : "5 stars"});

This will return all the articles which have a rating of 5.

Find can take multiple criteria

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.find({rating : "5 stars", published: "yesterday"});

This will return all the articles with a rating of 5, published yesterday.

Nested JSON :

var articleComments = {
    title: 'diskDB rocks',
    published: '2 days ago',
    comments: [{
        name: 'a user',
        comment: 'this is cool',
        rating: 2
    }, {
        name: 'b user',
        comment: 'this is ratchet',
        rating: 3
    }, {
        name: 'c user',
        comment: 'this is awesome',
        rating: 2
var savedArticle = db.articles.save([articleComments);
foundArticles = db.articles.find({rating : 2});

Since diskDB is mostly for light weight data storage, avoid nested structures and huge datasets.


var db = require('diskdb');
db.connect('/examples/db', ['articles']);

If you do not pass a query, diskDB will return the first article in the collection. If you pass a query, it will return first article in the filtered data.

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.findOne({_id: '0f6047c6c69149f0be0c8f5943be91be'});

Update Collection

db.collectionName.update(query, data, options);

You can also update one or many objects in the collection

options = {
    multi: false, // update multiple - default false
    upsert: false // if object is not found, add it (update-insert) - default false


var db = require('diskdb');
db.connect('/examples/db', ['articles']);
var query = {
  title : 'diskDB rocks'
var dataToBeUpdate = {
  title : 'diskDB rocks again!',
var options = {
   multi: false,
   upsert: false
var updated = db.articles.update(query, dataToBeUpdate, options);
console.log(updated); // { updated: 1, inserted: 0 }

Remove Collection

db.collectionName.remove(query, multi);

You can remove the entire collection (including the file) or you can remove the matched objects by passing in a query. When you pass a query, you can either delete all the matched objects or only the first one by passing multi as false. The default value of multi is true.

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove({rating : "5 stars"});
var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove({rating : "5 stars"}, true); // remove all matched. Default - multi = true
var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove({rating : "5 stars"}, false); // remove only the first match

Using remove without any params will delete the file and will remove the db instance.

var db = require('diskdb');
db.connect('/examples/db', ['articles']);

After the above operation db.articles is undefined.



Will return the count of objects in the Collection

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.count(); // will give the count


Refer to the examples folder.


To validate diskDB's performance and to check if it meets your needs, you can clone this repo and run

$ node performance/time.js

An average of few tests (run on OS X - 10.9.3 | 2.9GHZ i7 | 8GB 1600MHz DDR3) can be found below

Time taken to process x number of objects (in ms) vs Action Performed

# of objects 1 1000 10000 100000 1000000
Save 1 ms 15 ms 137 ms 1728 ms 14425 ms
Find all without query 0 ms 2 ms 12 ms 204 ms 2923 ms
Find all with query 0 ms 2 ms 17 ms 738 ms 1985 ms
Find one without query 0 ms 1 ms 9 ms 791 ms 1676 ms
Find one with query 0 ms 1 ms 8 ms 219 ms 1410 ms
Update all records 1 ms 7 ms 61 ms 206 ms 48035 ms
Get count 0 ms 3 ms 11 ms 260 ms 2420 ms
Remove with query 0 ms 7 ms 59 ms 984 ms 48191 ms
Remove collection 0 ms 1 ms 4 ms 52 ms 154 ms
File size 0.000111 MB 0.116671 MB 1.196671 MB 12.26667 MB 125.66667 MB


See the CONTRIBUTING Guidelines

Release History

  • 0.1.x
    • Base Module with
      • Connect to a Folder
      • Access a Collection/File
      • Create Read Update Delete on JSON object
      • Minor fixes and tests
      • Performance improvements


Copyright (c) 2014 Arvind Ravulavaru. Licensed under the MIT license.


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