Edge Functions Examples / Transform HTTP Response

Transform responses

You can use Edge Functions to transform the content of an HTTP response. In this example, we transform the response of a request to /hello with a toUpperCase() function, using the query parameter method=transform.

import { Context } from "netlify:edge";

export default async (request: Request, context: Context) => {
  const url = new URL(request.url);

  // Look for the query parameter, and return if we don't find it
  if (url.searchParams.get("method") !== "transform") {

  const response = await context.next();
  const text = await response.text();
  return new Response(text.toUpperCase(), response);

This transform Edge Function is set up to run using the method=transform query parameter on any URL, using this entry in the netlify.toml file:

  function = "transform"
  path = "/*"

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What are Edge Functions?

Using JavaScript and TypeScript, Netlify Edge Functions give you the power to modify network requests to localize content, serve relevant ads, authenticate visitors, A/B test content, and much more! And this all happens at the Edge — directly from the worldwide location closest to each user.

To use Edge Functions on Netlify, add JavaScript or TypeScript files to an edge-functions directory in your project, and add [[edge_functions]] entries to your netlify.toml file.

Learn more in the docs.

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