Function parseDescriptors

lib/html/syntax.js:7442–7553

* @returns {void}

()

	 * @returns {void}
	 */
	function parseDescriptors() {
		// 9. Descriptor parser: Let error be no.
		let pError = false;

		// 10. Let width be absent.
		// 11. Let density be absent.
		// 12. Let future-compat-h be absent. (We're implementing it now as h)
		/** @type {number | undefined} */
		let width;
		/** @type {number | undefined} */
		let density;
		/** @type {number | undefined} */
		let height;
		/** @type {string | undefined} */
		let desc;

		// 13. For each descriptor in descriptors, run the appropriate set of steps
		// from the following list:
		for (let i = 0; i < descriptors.length; i++) {
			desc = descriptors[i];

			const lastChar = desc[desc.length - 1].charCodeAt(0);
			const value = desc.slice(0, Math.max(0, desc.length - 1));

			// If the descriptor consists of a valid non-negative integer followed by
			// a U+0077 LATIN SMALL LETTER W character
			if (
				NON_NEGATIVE_INTEGER_REGEXP.test(value) &&
				lastChar === SMALL_LETTER_W
			) {
				// If width and density are not both absent, then let error be yes.
				if (width || density) {
					pError = true;
				}

				const intVal = Number.parseInt(value, 10);

				// Apply the rules for parsing non-negative integers to the descriptor.
				// If the result is zero, let error be yes.
				// Otherwise, let width be the result.
				if (intVal === 0) {
					pError = true;
				} else {
					width = intVal;
				}
			}
			// If the descriptor consists of a valid floating-point number followed by
			// a U+0078 LATIN SMALL LETTER X character
			else if (
				FLOATING_POINT_REGEXP.test(value) &&
				lastChar === SMALL_LETTER_X
			) {
				// If width, density and future-compat-h are not all absent, then let error
				// be yes.
				if (width || density || height) {
					pError = true;
				}