astro/dist/core/head-propagation/resolver.js

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/**
* Resolves the effective propagation hint for a component.
*
* Priority: explicit factory hint -> component metadata -> `none`.
*
* @example
* A runtime-created head entry uses `propagation: 'self'`, so it propagates
* even when metadata says `none`.
*/
export function resolvePropagationHint(input) {
	const explicitHint = input.factoryHint ?? "none";
	if (explicitHint !== "none") {
		return explicitHint;
	}
	if (!input.moduleId) {
		return "none";
	}
	return input.metadataLookup(input.moduleId) ?? "none";
}
/** Returns true when a hint should register a component as a propagator. */
export function isPropagatingHint(hint) {
	return hint === "self" || hint === "in-tree";
}
/**
* Reads propagation metadata from an `SSRResult` + component factory.
*
* @example
* A compiled `.astro` module with metadata `in-tree` is treated as propagating
* when the factory does not set a stronger explicit hint.
*/
export function getPropagationHint(result, factory) {
	return resolvePropagationHint({
		factoryHint: factory.propagation,
		moduleId: factory.moduleId,
		metadataLookup: (moduleId) => result.componentMetadata.get(moduleId)?.propagation
	});
}