Generating Types

Supabase APIs are generated from your database, which means that we can use database introspection to generate type-safe API definitions.

Generating types using Supabase CLI#

The Supabase CLI is a single binary Go application that provides everything you need to setup a local development environment.

You can install the CLI via npm or other supported package managers. The minimum required version of the CLI is v1.8.1.

npm i supabase@">=1.8.1" --save-dev

npx supabase login

Generate types for your project to produce the types/supabase.ts file:

npx supabase gen types typescript --project-id "$PROJECT_REF" --schema public > types/supabase.ts

After you have generated your types, you can use them in src/index.ts

import { NextApiRequest, NextApiResponse } from 'next'
import { createClient } from '@supabase/supabase-js'
import { Database } from '../types/supabase'
const supabase = createClient<Database>(
  process.env.NEXT_PUBLIC_SUPABASE_URL,
  process.env.SUPABASE_SECRET_KEY
)
export default async (req: NextApiRequest, res: NextApiResponse) => {
  const allOnlineUsers = await supabase.from('users').select('*').eq('status', 'ONLINE')
  res.status(200).json(allOnlineUsers)
}

Update types automatically with GitHub Actions#

One way to keep your type definitions in sync with your database is to set up a GitHub action that runs on a schedule.

Add the script above to your package.json to run it using npm run update-types

"update-types": "npx supabase gen types typescript --project-id \"$PROJECT_REF\" > types/supabase.ts"

Create a file .github/workflows/update-types.yml with the following snippet to define the action along with the environment variables. This script will commit new type changes to your repo every night.

name: Update database types
on:
  schedule:
    # sets the action to run daily. You can modify this to run the action more or less frequently
    - cron: '0 0 * * *'
jobs:
  update:
    runs-on: ubuntu-latest
    env:
      SUPABASE_ACCESS_TOKEN: ${{ secrets.ACCESS_TOKEN }}
      PROJECT_REF: <your-project-id>
    steps:
      - uses: actions/checkout@v2
        with:
          persist-credentials: false
          fetch-depth: 0
      - uses: actions/setup-node@v2.1.5
        with:
          node-version: 16
      - run: npm run update-types
      - name: check for file changes
        id: git_status
        run: |
          echo "::set-output name=status::$(git status -s)"
      - name: Commit files
        if: ${{contains(steps.git_status.outputs.status, ' ')}}
        run: |
          git add types/database/index.ts
          git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git config --local user.name "github-actions[bot]"
          git commit -m "Update database types" -a
      - name: Push changes
        if: ${{contains(steps.git_status.outputs.status, ' ')}}
        uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          branch: ${{ github.ref }}

Alternatively, you can use a community-supported GitHub action: generate-supabase-db-types-github-action.

Resources#

Generating Supabase types with GitHub Actions

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