astroHeadBuildPlugin() — astro Function Reference

Architecture documentation for the astroHeadBuildPlugin() function in index.ts from the astro codebase.

Function typescript CoreAstro RenderingEngine

Entity Profile

CoreAstro→ RenderingEngine→ astroHeadBuildPlugin() — astro Function Reference

Dependency Diagram

graph TD
  62f8b26a_0aeb_6311_c36a_82d2d99343a2["astroHeadBuildPlugin()"]
  bf5798b6_a592_be5c_0413_36786059a0dc["index.ts"]
  62f8b26a_0aeb_6311_c36a_82d2d99343a2 -->|defined in| bf5798b6_a592_be5c_0413_36786059a0dc
  style 62f8b26a_0aeb_6311_c36a_82d2d99343a2 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/astro/src/vite-plugin-head/index.ts lines 89–144

export function astroHeadBuildPlugin(internals: BuildInternals): vite.Plugin {
	return {
		name: 'astro:head-metadata-build',
		applyToEnvironment(environment) {
			return (
				environment.name === ASTRO_VITE_ENVIRONMENT_NAMES.ssr ||
				environment.name === ASTRO_VITE_ENVIRONMENT_NAMES.prerender
			);
		},
		generateBundle(_opts, bundle) {
			const map: SSRResult['componentMetadata'] = internals.componentMetadata;
			function getOrCreateMetadata(id: string): SSRComponentMetadata {
				if (map.has(id)) return map.get(id)!;
				const metadata: SSRComponentMetadata = {
					propagation: 'none',
					containsHead: false,
				};
				map.set(id, metadata);
				return metadata;
			}

			for (const [, output] of Object.entries(bundle)) {
				if (output.type !== 'chunk') continue;
				for (const [id, mod] of Object.entries(output.modules)) {
					const modinfo = this.getModuleInfo(id);

					// <head> tag in the tree
					if (modinfo) {
						const meta = getAstroMetadata(modinfo);
						if (meta?.containsHead) {
							for (const pageInfo of getTopLevelPageModuleInfos(id, this)) {
								let metadata = getOrCreateMetadata(pageInfo.id);
								metadata.containsHead = true;
							}
						}
						if (meta?.propagation === 'self') {
							for (const info of getParentModuleInfos(id, this)) {
								let metadata = getOrCreateMetadata(info.id);
								if (metadata.propagation !== 'self') {
									metadata.propagation = 'in-tree';
								}
							}
						}
					}

					// Head propagation (aka bubbling)
					if (mod.code && injectExp.test(mod.code)) {
						for (const info of getParentModuleInfos(id, this)) {
							getOrCreateMetadata(info.id).propagation = 'in-tree';
						}
					}
				}
			}
		},
	};
}