Make sure you have set up the RDB Server side. Please refer to this link.

Instalation

yarn add @hexalts/rdbc

Example

Once

Let's say you already have a MongoDB with collection cats with multiple documents of cat. You want to get it all for once.

First, you need to set up the RDB Configuration.

import RDB from '@hexalts/rdbc';

const instanceId = 'random UUIDv4'
const RDB = new RDB(
  {
    host: 'wss://broker.address.com:8883',
  },
  instanceId
);

You can try to generate an UUID v4 on this page, and make sure the client instanceId matches with the server instanceId. Otherwise it won't work.

Next step is to set up the database target and the collection we want to use.

const instance = RDB.Database('hexalts');
instance.Collection('cats');

Note that you only need to do this setup for once. It is dead simple. Then you can get all those cat like this.

const getAllCats = async () => {
  const result = await instance.Get();
  console.log(result);
};

getAllCats();

Stream

What if you want to listen to changes that affected any documents inside cats collection, while you get all documents inside cats collection at once? No worries, because it is as easy as this.

const watchThoseCats = async () => {
  const stream = instance.Stream('all');
  stream.on('data', (data) => {
    console.log(data);
  })
};

watchThoseCats();

Query

What if you want to get documents with multiple rules? Let's assume you have such documents

[
  {
    _id: '1',
    name: 'ciyo,
    age: 2,
    race: 'persian medium',
  },
  {
    _id: '2',
    name: 'izzy',
    age: 1,
    race: 'persian medium'
  },
  {
    _id: '3',
    name: 'mio,
    age: 3,
    race: 'persian medium'
  },
  {
    _id: '4',
    name: 'qio,
    age: 4,
    race: 'himalayan'
  },
]

Let's say you want to get any persian medium cats with age greater than 1. It goes like this.

const whereAreThoseCats = async () => {
  instance.Where('race', '==', 'persian medium')
  instance.Where('age', '>', 1)
  const stream = instance.Stream('all');
  stream.on('data', (data) => {
    console.log(data);
  });
};

whereAreThoseCats();

It will return

{
  _id: '1',
  name: 'ciyo,
  age: 2,
  race: 'persian medium',
}
{
  _id: '3',
  name: 'mio,
  age: 3,
  race: 'persian medium'
},

First, it will fetch you all documents which meets your rules. And then, once a document (which meets the rules) got changed, an event will be emitted over the stream.on with event name data, the data it emits is the one which got changed, it will not return the whole documents (which meets the rules) again because that will be inefficient.

Clear

A note to remember:

The Where() method actually push any query into the instance state, it means you need to Clear the Where condition to default every time you need a different query pattern.

But don't worry, because it is as easy as this.

instance.Clear();

Update

Let's say you inputted ciyo accidentally (it should be cio) and you want to update the document. Well, you got two ways to do that.

1. If you know the document id.

const changeCatName = async () => {
  instance.Where('_id', '==', '1')
  const result = await instance.Update({ name: 'cio' });
  console.log(result);
};

changeCatName();

2. If you don't remember the document id.

const changeCatName = async () => {
  instance.Where('name', '==', 'ciyo')
  const result = await instance.Update({ name: 'cio' });
  console.log(result);
};

changeCatName();

Delete

Let's say cio has just passed away and you want to move on, completely. Just like the Update method, you can use Where condition to delete it

1. If you know the document id.

const changeCatName = async () => {
  instance.Where('_id', '==', '1')
  const result = await instance.Delete();
  console.log(result);
};

changeCatName();

2. If you don't remember the document id.

const changeCatName = async () => {
  instance.Where('name', '==', 'ciyo')
  const result = await instance.Delete();
  console.log(result);
};

changeCatName();

Full API Documentation

For deeper understanding of Hexatls Realtime Database APIs, please refer to this dcumentation.