astro/dist/core/build/plugins/plugin-component-entry.js

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

import { ASTRO_VITE_ENVIRONMENT_NAMES } from "../../constants.js";
const astroEntryPrefix = "\0astro-entry:";
/**
* When adding hydrated or client:only components as Rolldown inputs, sometimes we're not using all
* of the export names, e.g. `import { Counter } from './ManyComponents.jsx'`. This plugin proxies
* entries to re-export only the names that the user is using.
*/
export function pluginComponentEntry(internals) {
	const componentToExportNames = new Map();
	mergeComponentExportNames(internals.discoveredHydratedComponents);
	mergeComponentExportNames(internals.discoveredClientOnlyComponents);
	for (const [componentId, exportNames] of componentToExportNames) {
		// If one of the imports has a dot, it's a namespaced import, e.g. `import * as foo from 'foo'`
		// and `<foo.Counter />`, in which case we re-export `foo` entirely and we don't need to handle
		// it in this plugin as it's default behaviour from Rolldown.
		if (exportNames.some((name) => name.includes(".") || name === "*")) {
			componentToExportNames.delete(componentId);
		} else {
			componentToExportNames.set(componentId, Array.from(new Set(exportNames)));
		}
	}
	function mergeComponentExportNames(components) {
		for (const [componentId, exportNames] of components) {
			if (componentToExportNames.has(componentId)) {
				componentToExportNames.get(componentId)?.push(...exportNames);
			} else {
				componentToExportNames.set(componentId, exportNames);
			}
		}
	}
	return {
		name: "@astro/plugin-component-entry",
		enforce: "pre",
		applyToEnvironment(environment) {
			return environment.name === ASTRO_VITE_ENVIRONMENT_NAMES.client;
		},
		config(config) {
			const rolldownInput = config.build?.rolldownOptions?.input;
			// Astro passes an array of inputs by default. Even though other Vite plugins could
			// change this to an object, it shouldn't happen in practice as our plugin runs first.
			if (Array.isArray(rolldownInput)) {
				// @ts-expect-error input is definitely defined here, but typescript thinks it doesn't
				config.build.rolldownOptions.input = rolldownInput.map((id) => {
					if (componentToExportNames.has(id)) {
						return astroEntryPrefix + id;
					} else {
						return id;
					}
				});
			}
		},
		resolveId: {
			filter: { id: new RegExp(`^${astroEntryPrefix}`) },
			handler(id) {
				return id;
			}
		},
		load: {
			filter: { id: new RegExp(`^${astroEntryPrefix}`) },
			async handler(id) {
				const componentId = id.slice(astroEntryPrefix.length);
				const exportNames = componentToExportNames.get(componentId);
				if (exportNames) {
					return { code: `export { ${exportNames.join(", ")} } from ${JSON.stringify(componentId)}` };
				}
			}
		}
	};
}
export function normalizeEntryId(id) {
	return id.startsWith(astroEntryPrefix) ? id.slice(astroEntryPrefix.length) : id;
}