Function parseBackgroundSize

packages/core/css/parser.ts:244–272

(value: string, start = 0, keyword = parseKeyword(value, start))

const backgroundSizeKeywords = new Set(['auto', 'contain', 'cover']);
export function parseBackgroundSize(value: string, start = 0, keyword = parseKeyword(value, start)): Parsed<BackgroundSize> {
	let end = start;
	if (keyword && backgroundSizeKeywords.has(keyword.value)) {
		end = keyword.end;
		const value = <'auto' | 'cover' | 'contain'>keyword.value;

		return { start, end, value };
	}

	// Parse one or two lengths... the other will be "auto"
	const firstLength = parsePercentageOrLength(value, end);
	if (firstLength) {
		end = firstLength.end;
		const secondLength = parsePercentageOrLength(value, firstLength.end);
		if (secondLength) {
			end = secondLength.end;

			return {
				start,
				end,
				value: { x: firstLength.value, y: secondLength.value },
			};
		} else {
			return { start, end, value: { x: firstLength.value, y: 'auto' } };
		}
	}

	return null;
}

const backgroundPositionKeywords = Object.freeze(new Set(['left', 'right', 'top', 'bottom', 'center']));
const backgroundPositionKeywordsDirection: {