Database-wide XPath evaluation in JavaScript in MarkLogic

database-xpath.sjs

/**
 * @param {string} path
 * @param {object} [bindings]
 * @param {string | Iterable<string>} [collection]
 * @return {Sequence<Node>}
 */
const xpath = (function _memo() {
	function isIterable(itr, ignoreStrings = false) {
		if ('string' === typeof itr) return !ignoreStrings;
		return Boolean(itr && itr[Symbol.iterator]);
	}
	function join(itr) {
		const quote = str => (str ? "'" + str + "'" : '');
		if (isIterable(itr, true)) {
			return `(${Array.from(itr)
				.map(quote)
				.join(',')})`; // Parens for an XPath Sequence
		}
		return quote(itr);
	}
	const node = new NodeBuilder().addNull().toNode(); // Total hack
	return function xpath(path, bindings, collection, options = { plan: false }) {
		const expression = `collection(${join(collection)})${
			'/' === path ? '' : path
		}`; // Special case: `collection()/` is not valid XPath
		if (options && options.plan) {
			return xdmp.xqueryEval(
				`xdmp:plan(${expression}${
					'number' === typeof options.plan ? `,${options.plan}` : ``
				})`
			);
		}
		return Node.prototype.xpath.call(node, expression, bindings);
	};
})();

// Example:
xpath('/'); // Sequence
xpath('/', {}, undefined, { plan: true }); // XMLNode