Homebase React

The React state management library for write-heavy applications

What and Why

As data and our need to annotate and organize it grows, so does our need for supporting state in write-heavy applications.

To solve this problem, modern write-heavy applications such as Superhuman, Roam Research, and Facebook Messenger built their own embedded data layers to enable these more sophisticated user experiences.

Homebase-react enables developers to access the same embedded datalog database as Roam Research through React hooks. You no longer have to build out a team or learn specialized tools like Clojure in order to build a delightful write-heavy application.

Testimonials

Homebase is executing on the vision of data usage, portability, and management we had when building Firebase. We never got there. I'm excited!

—James Tamplin, Founder/CEO of Firebase

Datalog is the future of end-user programming, personal productivity software, p2p software, etc.

—Chet Corcos, Founding Engineer of Notion

Install

# NPM
npm install homebase-react --save

# Yarn
yarn add homebase-react

Docs

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

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 lookupHelpers and initialData.

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

const config = {
  // Lookup helpers simplify relational queries at query time.
  // The helpers currently supported are:
  // `type: 'ref'` which is a relationship and
  // `unique: 'identity` which enforces a uniqueness constraint 
  // and lets you lookup entities by their unique attributes.
  lookupHelpers: {
    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 lookupHelpers 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.

Debugging tips

If you set debug to true in your configuration, you will be able to access the _recentlyTouchedAttributes attribute on entities. _recentlyTouchedAttributes will show any cached attributes for a given entity. This is helpful for approximating that entity's schema and values.

  <HomebaseProvider config={{ debug: true }}>
    <App/>
  </HomebaseProvider>

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

Limitations

Homebase React is currently not a good choice for read-heavy applications (e.g. Twitter, ecommerce). We plan to support these query patterns with our platform eventually.

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