astro/dist/vite-plugin-pages/pages.js

Astro is a modern site builder with web best practices, performance, and DX front-of-mind.

import { DEFAULT_COMPONENTS } from "../core/routing/default.js";
import { routeIsRedirect } from "../core/routing/helpers.js";
import { VIRTUAL_PAGE_MODULE_ID } from "./const.js";
import { getVirtualModulePageName } from "./util.js";
import { ASTRO_VITE_ENVIRONMENT_NAMES } from "../core/constants.js";
export const VIRTUAL_PAGES_MODULE_ID = "virtual:astro:pages";
const VIRTUAL_PAGES_RESOLVED_MODULE_ID = "\0" + VIRTUAL_PAGES_MODULE_ID;
/**
* Filters routes for a specific build environment.
*
* Redirect target routes do not need special handling here: they already
* appear in the routes list with their own `prerender` flag and are
* included when it matches `isPrerender`. At SSR runtime, redirect
* responses are generated from route metadata alone (no component is
* loaded), so the target's component is never needed in the SSR page map.
*/
export function getRoutesForEnvironment(routes, isPrerender) {
	const result = new Set();
	for (const route of routes) {
		if (route.prerender === isPrerender) {
			result.add(route);
		}
	}
	return result;
}
export function pluginPages({ routesList }) {
	return {
		name: "@astro/plugin-pages",
		enforce: "post",
		applyToEnvironment(environment) {
			return environment.name === ASTRO_VITE_ENVIRONMENT_NAMES.ssr || environment.name === ASTRO_VITE_ENVIRONMENT_NAMES.prerender;
		},
		resolveId: {
			filter: { id: new RegExp(`^${VIRTUAL_PAGES_MODULE_ID}$`) },
			handler() {
				return VIRTUAL_PAGES_RESOLVED_MODULE_ID;
			}
		},
		load: {
			filter: { id: new RegExp(`^${VIRTUAL_PAGES_RESOLVED_MODULE_ID}$`) },
			async handler() {
				const imports = [];
				const pageMap = [];
				let i = 0;
				// Filter routes based on the build environment to reduce memory usage.
				// Each environment only builds the pages it needs:
				// - SSR environment: builds only on-demand rendered pages (prerender: false)
				// - Prerender environment: builds only static pages (prerender: true)
				// - Other environments (e.g. client): get all routes
				const envName = this.environment.name;
				const isSSR = envName === ASTRO_VITE_ENVIRONMENT_NAMES.ssr;
				const isPrerender = envName === ASTRO_VITE_ENVIRONMENT_NAMES.prerender;
				const routes = isSSR || isPrerender ? getRoutesForEnvironment(routesList.routes, isPrerender) : new Set(routesList.routes);
				for (const route of routes) {
					if (routeIsRedirect(route)) {
						continue;
					}
					// Skip default components (404, server islands, etc.)
					if (DEFAULT_COMPONENTS.some((component) => route.component === component)) {
						continue;
					}
					const virtualModuleName = getVirtualModulePageName(VIRTUAL_PAGE_MODULE_ID, route.component);
					const module = await this.resolve(virtualModuleName);
					if (module) {
						const variable = `_page${i}`;
						// use the non-resolved ID to resolve correctly the virtual module
						imports.push(`const ${variable} = () => import("${virtualModuleName}");`);
						pageMap.push(`[${JSON.stringify(route.component)}, ${variable}]`);
						i++;
					}
				}
				const pageMapCode = `const pageMap = new Map([\n    ${pageMap.join(",\n    ")}\n]);\n\nexport { pageMap };`;
				return { code: [...imports, pageMapCode].join("\n") };
			}
		}
	};
}