Homebase React

The graph database for delightful React state management

Homebase React makes state management painless by enabling you to plug a relational graph database into your React application with just 3 lines of code. This is the same database that powers Roam Research and many other ClojureScript applications, but with an API that's familiar to React and JS developers.

Install

# NPM
npm install homebase-react --save

# Yarn
yarn add homebase-react

Docs

https://homebase.io/docs/homebase-react

Features

• The simplest and most declarative state management solution
• The power of a backend relational graph database, but without having to wait on the network
• Convenient JSON query syntax
• Powerful Clojure style Datalog query syntax if you need it
• Traverse your data graph like it's a big JSON object
• Backup your data to the cloud

Roadmap

1. Document integration with more backends
2. Swap Datascript out for Datahike
   1. Immutability
   2. History / Change Tracking
3. Persist to IndexedDB
4. Local-first conflict resolution for offline caching and sync between multiple devices

Examples

Live Demos

You can see our hosted live demos here

Code Examples

You can clone and run our React code examples here.

API Overview

HomebaseProvider

The HomebaseProvider wraps your React app and makes a relational database accessible to all of your components. Configure it with schema and initialData.

import { HomebaseProvider, useEntity, useTransact, useQuery } from 'homebase-react'

const config = {
  // Schema is not a type system,
  // it's a way to simplify relational queries at query time.
  // The schema currently supported is:
  // `type: 'ref'` which is a relationship and
  // `unique: 'identity` which enforces a uniqueness constraint 
  // and lets you lookup entities by their unique attributes.
  schema: {
    todo: {
      project: { type: 'ref', cardinality: 'one' },
      name: { unique: 'identity' }
    }
  },
  
  // Initial data is what it sounds like.
  // It's a transaction that runs on component mount.
  // Use it to hydrate your app.
  initialData: [
    { project: { id: -1, name: 'Do it', user: -2 } },
    { todo: { project: -1, name: 'Make it' } },
    { user: { id: -2, name: 'Arpegius' } }
  ]

  // Or relationships can be specified implicitly with nested JSON
  initialData: [
    { 
      todo: { 
        name: 'Make it',
        project: { 
          name: 'Do it', 
          user: { 
            name: 'Arpegius' 
          } 
        } 
      } 
    }
  ]
}

const RootComponent = () => (
  <HomebaseProvider config={config}>
    <App/>
  </HomebaseProvider>
)

useEntity and entity.get

Entities are the building blocks of the Homebase data model. They are like JSON objects with bonus features. In particular you can traverse arbitrarily deep relationships without actually denormalizing and nesting your data.

// You can get an entity by its id and get attributes off of it.
const [todo] = useEntity(2)
todo.get('id') // => 2
todo.get('name') // => 'Make it'

// Entities with unique attributes can also be retrieved by those attributes.
const [sameTodo] = useEntity({ todo: { name: 'Make it' } })
sameTodo.get('id') // => 2

// And most importantly you can traverse arbitrarily deep relationships.
sameTodo.get('project', 'user', 'name') // => 'Arpegius'

useTransact

Transactions let you create, update and delete multiple entities simultaneously. All changes will reactively update any components that depend on the changed data.

const transact = useTransact()

// A transaction is an array of nested objects and or arrays.
// Leaving the id blank will create a new entity.
transact([{ todo: { name: 'New Todo', project: 1 } }])

// Setting the id to a negative number is a temp id which 
// allows multiple entities to be related to each other on creation.
transact([
  { project: { id: -123, name: 'New Project' } },
  { todo: { project: -123, name: 'New Todo' } },
])

// Update an entity by including its id.
// NOTE: that only the included attributes will be updated.
transact([{ project: { id: 1, name: 'Changed Project Title' } }])

// To remove an attribute you have to explicitly set it to null.
transact([{ project: { id: 1, name: null } }])

// To delete an entire entity use retractEntity and its id
transact([['retractEntity', 1]])

useQuery

Use queries to return an array of entities that meet a given criteria. Our query API is powered by Datalog, but exposed as JSON similar to a JS SQL driver or MongoDB. Datalog is similar to SQL and is incredibly powerful. However, only a subset of features are currently available in JSON.

We will prioritize features based on community feedback so please open an issue if there's something you need. In the meantime you can further filter results with JS filter() and sort().

// Finds all todos with a name
const [todos] = useQuery({
  $find: 'todo',
  $where: { todo: { name: '$any' } }
})

// Returns an array of todo entities
todos
.sort((todo1, todo2) => todo1.get('name') > todo2.get('name') ? 1 : -1)
.map(todo => todo.get('name'))

useClient

This hook returns the current database client with some helpful functions for syncing data with a backend.

• client.dbToString() serializes the whole db including the schema to a string
• client.dbFromString('a serialized db string') replaces the current db
• client.dbToDatoms() returns an array of all the facts aka datoms saved in the db
  • datoms are the smallest unit of data in the database, like a key value pair but better
  • they are arrays of [entityId, attribute, value, transactionId, isAddedBoolean]
• client.addTransactListener((changedDatoms) => ...) adds a listener function to all transactions
  • use this to save data to your backend
• client.removeTransactListener() removes the transaction listener
  • please note that only 1 listener can be added per useClient scope
• client.transactSilently([{item: {name: ...}}]) like transact() only it will not trigger any listeners
  • use this to sync data from your backend into the client

Check out the Firebase example for a demonstration of how you might integrate a backend.

Development

yarn install
yarn dev

Open http://localhost:3000

Test

yarn install
yarn test

Contributing

Welcome and thank you! Writing docs, patches and features are all incredibly helpful and appreciated.

We only ask that you provide test coverage for code changes, and conform to our commit guidelines.

Authors

• Chris Smothers (@csmothers) – Homebase
• JB Rubinovitz (@rubinovitz) – Homebase