astro/.changeset/eleven-pens-glow.md

astro
minor

Deprecates the option for route-generating files to export a dynamic value for prerender. Only static values are now supported (e.g. export const prerender = true or = false). This allows for better treeshaking and bundling configuration in the future.

Adds a new "astro:route:setup" hook to the Integrations API to allow you to dynamically set options for a route at build or request time through an integration, such as enabling on-demand server rendering.

To migrate from a dynamic export to the new hook, update or remove any dynamic prerender exports from individual routing files:

// src/pages/blog/[slug].astro
- export const prerender = import.meta.env.PRERENDER

Instead, create an integration with the "astro:route:setup" hook and update the route's prerender option:

// astro.config.mjs
import { defineConfig } from 'astro/config';
import { loadEnv } from 'vite';

export default defineConfig({
  integrations: [setPrerender()],
});

function setPrerender() {
  const { PRERENDER } = loadEnv(process.env.NODE_ENV, process.cwd(), '');

  return {
    name: 'set-prerender',
    hooks: {
      'astro:route:setup': ({ route }) => {
        if (route.component.endsWith('/blog/[slug].astro')) {
          route.prerender = PRERENDER;
        }
      },
    },
  };
}