ElephantDB is a is a super simple in-memory node database. It supports adding, deleting, updating & querying. It is synchronous & is designed to be used when prototyping or stubbing APIs etc. Last tested in Node v6.3.0.

npm install --save elephant-db

This is a basic example which creates a db, adds some items & retrieves them. Any returned items are copies and can be safely mutated without effecting the actual items stored in the db.

const ElephantDB = require('elephant-db');

// You can set up different collections based like this. Collections
// are kind of like tables in which your data can and will be stored.
const db = new ElephantDB(['dogs', 'people']);

// You can add a single document like so:
db.select('people').add({
    id: 1, name: 'Steve', age: 38, job: 'developer'
});

// You can add multiple documents like so:
db.select('dogs').add([
    {
        id: 1, breed: 'Dachshund', hair: 'Short', name: 'Olive', age: 2
    },
    {
        id: 2, breed: 'Labrador', hair: 'Short', name: 'Albert', age: 10
    },
    {
        id: 3, breed: 'Cocker Spaniel', hair: 'Long', name: 'Bruce', age: 4
    }
]);

// You can then retrieve a single documents like so:
db.select('dogs').find({id: 3});
// {id: 3, breed: 'Cocker Spaniel', name: 'Bruce', age: 4}

// You can also find multiple documents:
db.select('dogs').findAll({hair: 'Short'});
// [
//     {id: 1, breed: 'Dachshund', hair: 'Short', name: 'Olive', age: 2},
//     {id: 2, breed: 'Labrador', hair: 'Short', name: 'Albert', age: 10}
// ]

// You can also provide a function to find documents:
db.select('dogs').findAll((dog) => dog.age < 5);
// [
//     {id: 1, breed: 'Dachshund', hair: 'Short', name: 'Olive', age: 2},
//     {id: 3, breed: 'Cocker Spaniel', hair: 'Long', name: 'Bruce', age: 4}
// ]

For examples of each method, check the tests.

Constructor to create an instance of ElephantDB. It takes a single array of string where each string is the name of a collection.

Selects a single collection within which you would like to find, delete, update etc.

Finds & returns the first document that matches. Takes either an object or function to find you a document. You can use an object that defines your query (e.g. .find({name: 'John'}) to find the first document with the name of John). Alternatively you can use a function that returns true or false base on whether a document matches (e.g. .find((person) => person.age <= 30)). Should no documents match your query, it will return undefined like Array.prototype.find()

Same as .find() but returns an array of all documents that match (or an empty array, if none match). If called without a query, returns all documents in the selected collection.

Finds & returns the first document that matches (like .find()) and updates that document. For example: .update({id: 1}, {age: 15}) would find a dog with the id of 1 and set it's age to 15 (in the example above). Alternatively a function can be used to update the document. For example:

db.update({id: 1}, (dog) => { 
    dog.age = dog.age * 2; 
})

Same as update() but updates all documents that matches.

Deletes & returns the first document that matches.

Deletes & returns all documents that match.

Returns all collections and stored objects.