Function generateSubsetData

packages/core/src/subsets.ts:64–92

(
	config: FontBuildConfig,
)

 * Generates the complete subset data map from raw file contents provided in the config.
 */
export const generateSubsetData = (
	config: FontBuildConfig,
): Map<string, SubsetDefinition> => {
	const subsetData = new Map<string, SubsetDefinition>();

	for (const name of config.subsets) {
		const fileContent = config.subsetSources?.[name];
		if (!fileContent) {
			// Missing subset sources make the build nondeterministic.
			throw new Error(`Missing subset source content for "${name}"`);
		}

		// A slicing strategy file will contain "subsets {" blocks.
		// Google-generated files don't have SlicingStrategy wrapper, just raw subset blocks
		if (fileContent.includes('subsets {')) {
			const slices = parseSlicingStrategy(fileContent);
			subsetData.set(name, {
				name,
				type: 'sliced',
				slices: slices.map((codepoints, i) => ({ index: i + 1, codepoints })),
			});
		} else {
			const codepoints = parseNamFile(fileContent);
			const unicodeRange = codepointsToRangeString(codepoints);
			subsetData.set(name, { name, type: 'range', unicodeRange, codepoints });
		}
	}
	return subsetData;
};