Function walk

packages/kit/src/core/sync/create_manifest_data/index.js:139–359

(depth, id, segment, parent)

		 * @param {import('types').RouteData | null} parent
		 */
		const walk = (depth, id, segment, parent) => {
			const unescaped = id.replace(/\[([ux])\+([^\]]+)\]/gi, (match, type, code) => {
				if (match !== match.toLowerCase()) {
					throw new Error(`Character escape sequence in ${id} must be lowercase`);
				}

				if (!/[0-9a-f]+/.test(code)) {
					throw new Error(`Invalid character escape sequence in ${id}`);
				}

				if (type === 'x') {
					if (code.length !== 2) {
						throw new Error(`Hexadecimal escape sequence in ${id} must be two characters`);
					}

					return String.fromCharCode(parseInt(code, 16));
				} else {
					if (code.length < 4 || code.length > 6) {
						throw new Error(
							`Unicode escape sequence in ${id} must be between four and six characters`
						);
					}

					return String.fromCharCode(parseInt(code, 16));
				}
			});

			if (/\]\[/.test(unescaped)) {
				throw new Error(`Invalid route ${id} — parameters must be separated`);
			}

			if (count_occurrences('[', id) !== count_occurrences(']', id)) {
				throw new Error(`Invalid route ${id} — brackets are unbalanced`);
			}

			if (/#/.test(segment)) {
				// Vite will barf on files with # in them
				throw new Error(`Route ${id} should be renamed to ${id.replace(/#/g, '[x+23]')}`);
			}

			if (/\[\.\.\.\w+\]\/\[\[/.test(id)) {
				throw new Error(
					`Invalid route ${id} — an [[optional]] route segment cannot follow a [...rest] route segment`
				);
			}

			if (/\[\[\.\.\./.test(id)) {
				throw new Error(
					`Invalid route ${id} — a rest route segment is always optional, remove the outer square brackets`
				);
			}

			const { pattern, params } = parse_route_id(id);

			/** @type {import('types').RouteData} */
			const route = {
				id,
				parent,