Function resolveFontFaces

packages/core/src/utils/faces.ts:22–114

(
	config: FontConfig,
	options: ResolveFontFaceOptions = {},
)

 * Get the full list of font faces to generate for a given font configuration.
 */
export const resolveFontFaces = (
	config: FontConfig,
	options: ResolveFontFaceOptions = {},
): FontFace[] => {
	const {
		id,
		family,
		subsets,
		weights,
		styles,
		unicodeRange = {},
		variable,
		formats = ['woff2'],
	} = config;

	const faces: FontFace[] = [];
	const isVariable = !!variable;
	const familyId = id ?? normalizeKebabCase(family);

	if (isVariable) {
		const axisKeys = getRequestedAxisKeys(variable, options.axisKeys);

		// Filter out ttf formats for variable fonts.
		const variableFormats = formats.filter(
			(format): format is WebFontFormat => format !== 'ttf',
		);

		// Generate one face per axis key, with the weight set to the closest available weight.
		for (const axisKey of axisKeys) {
			const axisConfig = pickAxisConfig(variable, axisKey);
			const cssWeight = axisConfig.wght
				? formatAxisValue(axisConfig.wght)
				: `${findClosestWeight(weights)}`;

			const stretch = getFaceStretch(axisKey, axisConfig);

			for (const subset of subsets) {
				for (const style of styles) {
					faces.push({
						subset,
						weight: cssWeight,
						style: getFaceStyle(axisKey, style, axisConfig),
						isVariable: true,
						unicodeRange: unicodeRange[subset] ?? '',
						sources: variableFormats.map((format) => ({
							format,
							filename: generateVariableFilename(
								familyId,
								subset,
								axisKey,
								style,
								0,
								format,
							),
						})),
						axisKey,
						stretch,
						sliceIndex: 0,