MarsDB is a lightweight client-side database. It's based on a Meteor's minimongo matching/modifying implementation. It's carefully written on ES6, have a Promise based interface and may be backed with any storage implementation (see plugins). It's also supports observable cursors.
MarsDB supports any kind of find/update/remove operations that Meteor's minimongo does. So, go to the Meteor docs for supported query/modifier operations.
You can use it in any JS environment (Browser, Electron, NW.js, Node.js).
- Promise based API
- Carefully written on ES6
- Very very flexible – just take a look to the plugins section
- Supports many of MongoDB query/modify operations – thanks to a Meteor's minimongo
- Flexible pipeline – map, reduce, custom sorting function, filtering. All with a sexy JS interface (no ugly mongo's aggregation language)
- Persistence API – all collections can be stored (and restored) with any kind of storage (in-memory, LocalStorage, LevelUP, etc)
- Observable queries - live queries just like in Meteor, but with simplier interface
- Reactive joins – out of the box
- In-memory storage (built-in default)
- LocalForage storage – fastest in-browser storage (InexedDB, WebSQL and fallback to localStorage)
- LocalStorage storage – not recommended, better prefer LocalForage
- LevelUP storage – lightweight server-less Node.js storage
- MongoDB wrapper – use MarsDB for comfortable work with MongoDB
- Validation via Mongoose – validate objects with Mongoose
Sometimes you can't use Meteor infrastructure. Maybe you need to build a custom client. Maybe you need to build a custom server with express and other modules. In meteor it can be done with a ton of hack. But the only reason why it's so ugly to do a simple things is because Meteor forces you to use their infrastructure. I'm trying to solve this issue with DDP client/server modules, based on MarsDB.
The ./dist folder contains already compiled to a ES5 code, but some polyfills needed. For using in a browser you must to include marsdb.polyfills.js before marsdb.min.js. In node.js you need to require('marsdb/polyfills').
It sets in a window/global: Promise, Set and Symbol.
import Collection from 'marsdb';
import LocalForageManager from 'marsdb-localforage';
// Default storage is in-memory
// Setup different storage managers
// (all documents will be save in a browser cache)
Collection.defaultStorageManager(LocalForageManager);
// Create collection wit new default storage
const users = new Collection('users');import Collection from 'marsdb';
import LocalStorageManager from 'marsdb-localstorage';
// Set some defaults and create collection
Collection.defaultStorageManager(LocalStorageManager);
const users = new Collection('users');
// But it may be useful to create in-memory
// collection without defined defaults
// (for example to save some session state)
const session = new Collection('session', {inMemory: true});const posts = new Collection('posts');
posts.find({author: 'Bob'})
.project({author: 1})
.sort(['createdAt'])
.then(docs => {
// do something with docs
});An order of pipeline methods invokation is important. Next pipeline operation gives as argument a result of a previous operation.
const posts = new Collection('posts');
// Get number of all comments in the DB
posts.find()
.limit(10)
.sortFunc((a, b) => a - b + 10)
.filter(doc => Matsh.sqrt(doc.comment.length) > 1.5)
.map(doc => doc.comments.length)
.reduce((acum, val) => acum + val)
.then(result => {
// result is a number of all comments
// in all found posts
});
// Result is `undefined` because posts
// is not exists and additional processing
// is not ran (thanks to `.ifNotEmpty()`)
posts.find({author: 'not_existing_name'})
.aggregate(docs => docs[0])
.ifNotEmpty()
.aggregate(user => user.name)Observable cursor returned by a find and findOne methods of a collection. Updates of the cursor is batched and debounced (default batch size is 20 and debounce time is 1000 / 15 ms). You can change the paramters by batchSize and debounce methods of an observable cursor (methods is chained).
const posts = new Collection('posts');
const stopper = posts.find({tags: {$in: ['marsdb', 'is', 'awesome']}})
.observe(docs => {
// invoked on every result change
// (on initial result too)
stopper.stop(); // stops observing
}).then(docs => {
// invoked once on initial result
// (after `observer` callback)
});const users = new Collection('users');
const posts = new Collection('posts');
posts.find()
.join(doc => {
// Return a Promise for waiting of the result.
return users.findOne(doc.authorId).then(user => {
doc.authorObj = user;
// any return is ignored
});
})
.join(doc => {
// For reactive join you must invoke `observe` instead `then`
// That's it!
return users.findOne(doc.authorId).observe(user => {
doc.authorObj = user;
});
})
.join((doc, updated) => {
// Also any other “join” mutations supported
doc.another = _cached_data_by_post[doc._id];
// Manually update a joined parameter and propagate
// update event from current cursor to a root
// (`observe` callback invoked)
setTimeout(() => {
doc.another = 'some another user';
updated();
}, 10);
})
// Or just pass join spec object for fast joining
// (only one `find` will be produced for all posts)
.join({ authorId: users }) // posts[i].authorId will be user object
.observe((posts) => {
// do something with posts with authors
// invoked any time when posts changed
// (and when observed joins changed too)
})const posts = new Collection('posts');
posts.insert({text: 'MarsDB is awesome'}).then(docId => {
// Invoked after persisting document
})
posts.insertAll(
{text: 'MarsDB'},
{text: 'is'},
{text: 'awesome'}
).then(docsIds => {
// invoked when all documents inserted
});const posts = new Collection('posts');
posts.update(
{authorId: {$in: [1, 2, 3]}},
{$set: {text: 'noop'}}
).then(result => {
console.log(result.modified) // count of modified docs
console.log(result.updated) // array of updated docs
console.log(result.original) // array of original docs
});
// Upsert (insert when nothing found)
posts.update(
{authorId: "123"},
{$set: {text: 'noop'}},
{upsert: true}
).then(result => {
// { authorId: "123", text: 'noop', _id: '...' }
});const posts = new Collection('posts');
posts.remove({authorId: {$in: [1,2,3]}})
.then(removedDocs => {
// do something with removed documents array
});- Indexes support for some kind of simple requests {a: '^b'}, {a: {$lt: 9}}
- Documentation
I'm waiting for your pull requests and issues.
Don't forget to execute gulp lint before requesting. Accepted only requests without errors.
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