Add support for query.one, mixins, and DOM queries, and make the Riot query optional

src/index.js

@@ -29,10 +29,13 @@ function recurseTags(tag) {
 
 function createQuery(query) {
 	let {riotQuery, domQuery} = queryParser.parse(query);
+	let tagObtainer;
+
+	if (riotQuery != null) {
 		let flattenedQueries = flatten(riotQuery);
 		tagQueries(flattenedQueries);
 
-	return function traverse(tag) {
+		tagObtainer = function(tag) {
 			let results = [];
 
 			flattenedQueries.forEach((subQuery) => {
@@ -64,17 +67,57 @@ function createQuery(query) {
 
 			return dedupe(results, result => result._riot_id);
 		}
+	} else {
+		tagObtainer = function(tag) {
+			return [tag];
+		}
+	}
+
+	return function traverse(tag) {
+		let riotResults = tagObtainer(tag);
+
+		if (domQuery == null) {
+			return riotResults;
+		} else {
+			let domElements = [];
+
+			riotResults.forEach((foundTag) => {
+				domElements = domElements.concat(Array.from(foundTag.root.querySelectorAll(domQuery)));
+			});
+
+			return domElements;
+		}
+	}
 }
 
 let queryCache = {};
 
-module.exports = function(tag, query) {
-	if (queryCache[query] == null) {
-		queryCache[query] = createQuery(query);
+function query(tag, queryString) {
+	if (queryCache[queryString] == null) {
+		queryCache[queryString] = createQuery(queryString);
 	}
 
 	// TODO: DOM traversal
 
-	return queryCache[query](tag);
+	return queryCache[queryString](tag);
+}
+
+query.one = function queryOne(tag, queryString) {
+	let results = query(tag, queryString);
+
+	if (results.length === 0) {
+		throw new Error(`No matches found for query ${queryString}`);
+	} else {
+		return results[0];
+	}
+}
+
+/* For use with `riot.mixin(query.mixin)`: */
+query.mixin = {
+	init: function() {
+		this.query = query.bind(null, this);
+		this.queryOne = query.one.bind(null, this);
+	}
 }
 
+module.exports = query;

src/query.pegjs

@@ -19,7 +19,7 @@
 }
 
 start
-	= riotQuery:riotQuery domQuery:domQuerySuffix? { return combineFinal(riotQuery, domQuery) }
+	= riotQuery:riotQuery? domQuery:domQuerySuffix? { return combineFinal(riotQuery, domQuery) }
 
 riotQuery
 	= segment:riotQuerySegment subSegments:("/" riotQuerySegment)* { return concatRepeat(segment, subSegments, 1); }