Search refinement and bugfixing

Fixes #242

lib/search.js

@@ -19,14 +19,35 @@
 		texts.push({text: text.toLowerCase(), content});
 	};
 	scope.search = function(search){
-		search = search.toLowerCase();
-		const result = [];
-		texts.forEach(function(text){
-			if (text.text.indexOf(search) !== -1){
-				result.push(text.content);
-			}
+		const resultSets = search.toLowerCase().split(/\s+/).filter(function(term){
+			return term.trim();
+		}).map(function(term){
+			return new RegExp(term);
+		}).map(function(term){
+			const matching = new Set();
+			texts.forEach(function(text){
+				if (term.test(text.text)){
+					matching.add(text.content);
+				}
+			});
+			return matching;
 		});
-		return result;
+		if (resultSets.length){
+			return Array.from(
+				resultSets.reduce(function(previousSet, set){
+					var andSet = new Set();
+					set.forEach(function(entry){
+						if (previousSet.has(entry)){
+							andSet.add(entry);
+						}
+					});
+					return andSet;
+				})
+			);
+		}
+		else {
+			return [];
+		}
 	};
 	const searchListeners = [];
 	scope.init = function(){