Step 1: Set Up a Supabase Project

 

To get started with optimistic UI using Supabase, you first need to set up a Supabase project.

• Visit Supabase and sign in or create an account.
• Once logged in, click on “New Project” and fill out the required details to create your project.
• Note the API URL and the public API key provided by Supabase, as you will use these in your application.

 

Step 2: Initialize Your Project with Supabase

 

You need to initialize your project to start using Supabase.

• Create a new directory for your project:

  
  mkdir my-supabase-project
  cd my-supabase-project
  

• Initialize a new Node.js project with the following command:

npm init -y

• Install the Supabase client library:

npm install @supabase/supabase-js

• Create a new file named index.js and add the following code to initialize Supabase:

const { createClient } = require('@supabase/supabase-js')

const supabaseUrl = 'YOUR_SUPABASE_URL'
const supabaseAnonKey = 'YOUR_SUPABASE_ANON\_KEY'

const supabase = createClient(supabaseUrl, supabaseAnonKey)

Replace YOUR_SUPABASE_URL and YOUR_SUPABASE_ANON_KEY with the respective values from your Supabase project.

 

Step 3: Create a Table in Supabase

 

In your Supabase dashboard, you need to create a table that your application will interact with.

• Navigate to the “Table Editor.”
• Create a new table, for example, todos, with fields for id, task, is_complete (boolean).
• Ensure you have set up row-level security (RLS) policies to allow read and write access.

 

Step 4: Set Up Frontend Environment

 

Now, set up a frontend environment to display and dynamically update tasks.

• Use a frontend library like React, Vue, or Angular. Here, we'll demonstrate using React.
• Inside your project directory, create the React environment:

npx create-react-app my-supabase-ui
cd my-supabase-ui
npm install @supabase/supabase-js

• In src/App.js, initialize Supabase similar to how we did in index.js.

 

Step 5: Fetch Initial Data

 

• Fetch your data from the Supabase table and display it using your frontend framework. In src/App.js:

import React, { useEffect, useState } from 'react'
import { createClient } from '@supabase/supabase-js'

const supabaseUrl = 'YOUR_SUPABASE_URL'
const supabaseAnonKey = 'YOUR_SUPABASE_ANON\_KEY'
const supabase = createClient(supabaseUrl, supabaseAnonKey)

function App() {
  const [todos, setTodos] = useState([])

  useEffect(() => {
    const fetchData = async () => {
      const { data, error } = await supabase
        .from('todos')
        .select('\*')
      if (error) console.log('Error fetching data: ', error)
      else setTodos(data)
    }

    fetchData()
  }, [])

  return (
    

      
Optimistic UI with Supabase
      

        {todos.map(todo => (
          
{todo.task}
        ))}
      
    
  )
}

export default App

 

Step 6: Implement Optimistic UI

 

• Add functionality to update the user interface optimistically when a new task is added.

• Modify src/App.js to include a function to add tasks:

function App() {
  const [todos, setTodos] = useState([])
  const [newTask, setNewTask] = useState('')

  // Fetching Data
  useEffect(() => {
    const fetchData = async () => {
      const { data, error } = await supabase
        .from('todos')
        .select('\*')
      if (error) console.log('Error fetching data: ', error)
      else setTodos(data)
    }
    fetchData()
  }, [])

  // Adding tasks
  const addTask = async e => {
    e.preventDefault()

    const task = { task: newTask, is\_complete: false }

    // Optimistically update UI
    setTodos([...todos, task])
    setNewTask('')

    const { error } = await supabase
      .from('todos')
      .insert([task])
      
    if (error) {
      // Revert if there's an error
      console.log('Error inserting new task: ', error)
      setTodos(todos)
    }
  }

  return (
    

      
Optimistic UI with Supabase
      

         setNewTask(e.target.value)}
        />
        Add Task
      
      

        {todos.map((todo, index) => (
          
{todo.task}
        ))}
      
    
  )
}

export default App

In the addTask function, the task is added to the existing list of tasks immediately. If there's an error during the insertion into the database, it rolls back to the previous state.

 

Step 7: Test the Application

 

• Run the React app with:

npm start

• Try adding a new task. It should appear immediately in the list, demonstrating the optimistic UI. If there’s an error, the task should disappear from the list.

This completes the setup for implementing an optimistic UI with Supabase. Adjust field names, error handling, and environment URLs/settings as necessary for your specific use case.