Creating Edge Functions with Deno in Supabase - Try It Yourself

Creating Edge Functions with Deno

📖 Scenario: You are building a simple serverless function using Deno on Supabase Edge Functions. This function will respond to HTTP requests with a greeting message. Edge Functions run close to users for fast responses.

🎯 Goal: Create a basic Edge Function using Deno that returns a JSON greeting message when called.

📋 What You'll Learn

Create a new Edge Function file named hello.ts.

Define a handler function that accepts a Request object.

Return a JSON response with a greeting message.

Export the handler as the default export.

💡 Why This Matters

🌍 Real World

Edge Functions let you run code close to users without managing servers. This improves speed and scalability for web apps.

💼 Career

Knowing how to write and deploy Edge Functions is valuable for cloud developers working with serverless architectures and modern backend services.

1

Create the Edge Function file

Create a new file named hello.ts and define an async function called handler that accepts a single parameter request of type Request. For now, leave the function body empty.

Supabase

async function handler(request: Request) {
  // Your code here
}

Hint

Start by writing the function signature for handler with async and a request parameter.

2

Create a JSON response object

Inside the handler function, create a constant called responseBody and assign it an object with a single key message and value "Hello from Supabase Edge Function!".

Supabase

async function handler(request: Request) {
  // Create responseBody object here
  // Your code here
}

Hint

Use const responseBody = { message: "Hello from Supabase Edge Function!" } inside the function.

3

Return the JSON response

Return a new Response object from the handler function. Use JSON.stringify(responseBody) as the body, and set the Content-Type header to application/json.

Supabase

async function handler(request: Request) {
  const responseBody = { message: "Hello from Supabase Edge Function!" };
  // Return JSON response here
  // Your code here
}

Hint

Use return new Response(JSON.stringify(responseBody), { headers: { "Content-Type": "application/json" } }).

4

Export the handler as default

Add a default export statement at the end of the file to export the handler function.

Supabase

async function handler(request: Request) {
  const responseBody = { message: "Hello from Supabase Edge Function!" };
  return new Response(JSON.stringify(responseBody), {
    headers: { "Content-Type": "application/json" }
  });
}
// Export handler as default
// Your code here

Hint

Write export default handler; at the end of the file.