astro/dist/vite-plugin-environment/rolldown-plugin-astro-scan.js

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

import { readFile } from "node:fs/promises";
import { transform } from "@astrojs/compiler-rs";
/**
* Replaces Vite's regex-based `.astro` dependency scan with the scripts the Astro compiler hoists,
* which are the same scripts `vite-plugin-astro` serves as `?astro&type=script` modules. Markup-like
* text in frontmatter or template expressions is never mistaken for a script, and scripts Astro
* renders inline (`is:inline`, or any attribute other than `src`) are not scanned.
*
* @see https://github.com/withastro/astro/issues/18068
*/
export function rolldownAstroClientScanPlugin() {
	const scripts = new Map();
	return {
		name: "astro:client-dep-scan",
		resolveId(source, importer) {
			if (scripts.has(source)) return source;
			const parentScript = importer && scripts.get(importer);
			if (parentScript) {
				return this.resolve(source, parentScript.importer, { skipSelf: true });
			}
		},
		async load(id) {
			const script = scripts.get(id);
			if (script) {
				// The scan's TypeScript transform drops unused imports, but Astro's tsconfig enables
				// `verbatimModuleSyntax`, so they are still requested at runtime.
				const imports = this.parse(script.code, { lang: "ts" }).body.flatMap((node) => node.type === "ImportDeclaration" && node.importKind !== "type" ? [`\nimport ${JSON.stringify(node.source.value)};`] : []);
				return {
					code: script.code + imports.join(""),
					moduleType: "ts"
				};
			}
			if (!id.endsWith(".astro")) return;
			const { scripts: hoisted } = transform(await readFile(id, "utf-8"), { filename: id });
			const code = hoisted.map((hoistedScript, index) => {
				if (hoistedScript.type === "external") return `import ${JSON.stringify(hoistedScript.src)};`;
				// The `.ts` extension lets Vite's scan transform for `import.meta.glob` run on the script.
				const scriptId = `${id}?astro-client-dep-scan=${index}&lang.ts`;
				scripts.set(scriptId, {
					code: hoistedScript.code,
					importer: id
				});
				return `import ${JSON.stringify(scriptId)};`;
			});
			return {
				code: [...code, "export default {};"].join("\n"),
				moduleType: "js"
			};
		}
	};
}