Mongfaux

Mongfaux is a reverse engineering of the mongodb interface. It saves the data as flat JSON files for fast prototyping and/or a Git-able datastore.

Shortcomings

Mongfaux is <600 lines of code and only attempts to replicate a small, heavily used, portion of the API. You should consider using a real database if you need more.
Mongfaux uses a simple string for the auto-generated "_id" field. I would suggest ignoring _id and creating your own "id" field using something like shortid. Alternatively you can manually set your own _id with require('mongodb').ObjectID.
Doesn't have your back with things like enforcing unique keys. Inserting two documents with the same "_id" will pass through no problem.
Does not produce very helpful errors
Very little consideration has been given to performance. Use mongoDB if that's a priority!
Callbacks didn't make the cut, use promises

Installation

npm install mongfaux

Usage

const db = require('mongfaux');

await db.collection('book').insertOne({author: 'foobar', title: 'Mongfaux'});

let books = await db.collection('book').find({}).toArray();

//.json files saved in process.cwd()/mongfaux/ by default

Multiple instances

const Mf = require('mongfaux');
const db1 = Mf.instance();
const db2 = Mf.instance();

db1.name('db1');
db2.name('db2');

//mongfaux/
//--db1/
//--db2/

Queries

let longJohnBooks = await db.collection('books').find({
    'author.firstName': 'John',
    'pages': {
        '$gte': 300
    }
}).toArray();

Understands nested queries like {'author.firstName': 'John'}
Accepts the following operators: $ne $gt $gte $lt $lte $in $nin $eq $exists
Can query values in a document array. {tags: 'blue'} will select {_id: '', tags: ['blue', green]}, but does not understand array query operators ($all, $elemMatch, $size)

Updates

await db.collection('book').insertOne({
    title: 'Good Book',
    author: 'John Doe',
    reviews: 'positive'
})
await db.collection('book').findOneAndUpdate(
     {title: 'Good Book'},
     {
         $rename: {title: 'lametitle'},
         $set: {author: 'Jane Doe'},
         $unset: {reviews: true}
     }
 );
/*{
    lametitle: 'Good Book',
    author: 'Jane Doe'
}*/

Doesn't accept shorthand updates like {author: 'Jane Doe'}
Accepts the following operators: $inc $min $max $mul $set $unset $rename $currentDate $addToSet $pop $push

Projections

let firstNames = await db.collection('book').find({}).project({
    {'author.firstName': 1, _id: 0, title: 1}
}).toArray();
/*[
    {author: {firtName: 'John'}, title: 'My Book'},
    {author: {firstName: 'Jane'}, title: 'Hello World'}
]*/

Accepts nested keys
Doesn't accept operators

API

Db

.collection(name)

Returns the collection. If the collection doesn't exist, a new collection and .json file will be created

.parentDirectory( directory )

Sets the parent directory of the "mongfaux" folder where .json files are saved. Directory is process.cwd() by default.

.db( dbname )

Sets the database name. Also uses "mongfaux/dbname" folder for .json files. Has "name()" alias.

Collection

.createIndex()

Does nothing

.insertOne( document ) -> Promise

Autogenerates _id key and inserts document into the collection

Returns e.g. {insertedCount: 1, ops: [document], insertedId: id}

.insertMany( documents ) -> Promise

Autogenerated _id key for each document and inserts each document.

Returns e.g. {insertedCount: 1, ops: documents, insertedIds: []}

.find( query, options ) -> Cursor

Finds one or more documents in the collection.

Requires .toArray() to return a promise.
Option object accepts: sort, skip, limit, and projection

.findOne( query ) -> Promise

Finds a single document.

Does not require .toArray()
Options object accepts: sort, skip, and projection options

.findOneAndUpdate( query, update, options ) -> Promise

Finds and updates a single document.

Returns e.g. {value: document, ok: 1}.
Options object accepts: sort, upsert, returnOriginal, projection
returnOriginal is true by default

.updateOne( query, update, options ) -> Promise

Updates a single document without returning any documents.

Returns e.g. {matchedCount: 1, modifiedCount: 1, upsertedId: id}
Options object accepts: upsert

.updateMany( query, update, options ) -> Promise

Updates many documents without returning any documents.

Returns e.g {matchedCount: 1, modifiedCount: 1, upsertedId: id}
Options object accepts: upsert

.findOneAndDelete ( query, options ) -> Promise

Finds, returns, and deletes a single document.

Returns e.g. {ok: 1, value: document}
Options object accepts: sort, projection

.deleteOne ( query ) -> Promise

Deletes a single document without returning any documents.

Returns e.g. {deletedCount: 1}

.deleteMany ( query ) -> Promise

Delete multiple documents without returning any documents.

Returns e.g. {deletedCount: 1}

.findOneAndReplace ( query, document, options ) -> Promise

Finds a single document and replaces it.

Returns e.g. {value: }
Options object accepts: sort, upsert, returnOriginal
returnOriginal is true by default

.replaceOne ( query, document, options ) -> Promise

Replaces a document without returning any documents.

Returns e.g. {matchedCount: 1, modifiedCount: 1, upsertedId: id}
Options object accepts: upsert

Cursor

.project ( object ) -> Cursor

Sets a field projection for the query result

.skip ( amount ) -> Cursor

Skips over a number of documents at the beginning of the query result

.limit ( amount ) -> Cursor

Specifies the maximum number of documents to return

.max ( indexBounds ) -> Cursor

Specifies the exclusive upper bound for a specific index

e.g {countingid: 10000}

.min ( indexBounds ) -> Cursor

Specifies the inclusive lower bound for a specific index

e.g {countingid: 10}

.sort ( object ) -> Cursor

e.g {date: -1} for sorting by date in a descending order

.toArray () -> Promise

Finishes query and returns the result.

.count () -> Promise

Finishes query and returns the number of documents.

mongfaux