astro/dist/assets/fonts/core/validate-family-properties.js

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/**
* Keywords allowed by the `font-weight` descriptor, mapped to their numeric value.
*/
const WEIGHT_KEYWORDS = {
	normal: 400,
	bold: 700
};
/**
* Parses a weight (eg. `"400"`, `"bold"` or the variable range `"100 900"`) into a
* `[min, max]` range. Returns `null` when the value can't be interpreted: in that case
* we prefer staying silent over warning wrongly.
*/
function parseWeightRange(weight) {
	const parts = weight.trim().split(/\s+/).filter(Boolean);
	if (parts.length === 0 || parts.length > 2) {
		return null;
	}
	const values = parts.map((part) => WEIGHT_KEYWORDS[part] ?? Number(part));
	if (values.some((value) => !Number.isFinite(value))) {
		return null;
	}
	return [values[0], values[1] ?? values[0]];
}
/**
* A weight is available if it's covered by one of the weights the provider exposes.
* Providers may expose variable ranges, so `500` is available if `100 900` is.
*/
function isWeightAvailable(weight, availableWeights) {
	const range = parseWeightRange(weight);
	if (!range) {
		return true;
	}
	return availableWeights.some((availableWeight) => {
		const availableRange = parseWeightRange(availableWeight);
		if (!availableRange) {
			return true;
		}
		return range[0] >= availableRange[0] && range[1] <= availableRange[1];
	});
}
/**
* Warns about values configured for a family that its provider can't serve, eg. a weight
* or a subset a font family does not have. We only check values that are explicitly
* configured: defaults are handled by providers themselves.
*/
export async function validateFamilyProperties({ family, fontResolver, logger, bold }) {
	// Providers are not required to implement this, and they return no properties for
	// families they don't know about. In both cases, there's nothing to check against.
	const properties = await fontResolver.getFontProperties({
		familyName: family.name,
		provider: family.provider
	});
	if (!properties) {
		return;
	}
	const check = (key, configured, isAvailable) => {
		const available = properties[key];
		if (!configured || !available || available.length === 0) {
			return;
		}
		const unsupported = configured.filter((value) => !isAvailable(value, available));
		if (unsupported.length === 0) {
			return;
		}
		logger.warn("assets", `The ${bold(family.name)} font family does not support the following ${key}: ${unsupported.join(", ")}. Available ${key}: ${available.join(", ")}. Review your configuration.`);
	};
	const includes = (value, available) => available.includes(value);
	check("weights", family.weights, isWeightAvailable);
	check("styles", family.styles, includes);
	check("subsets", family.subsets, includes);
	check("formats", family.formats, includes);
}