Shorten some util code

Author: zbjornson

lib/validation.js

@@ -10,24 +10,18 @@ exports.validateMetricName = function (name) {
 	return metricRegexp.test(name);
 };
 
-exports.validateLabelName = function (names) {
-	let valid = true;
-	(names || []).forEach(name => {
-		if (!labelRegexp.test(name)) {
-			valid = false;
-		}
-	});
-	return valid;
+exports.validateLabelName = function (names = []) {
+	return names.every(name => labelRegexp.test(name));
 };
 
 exports.validateLabel = function validateLabel(savedLabels, labels) {
-	Object.keys(labels).forEach(label => {
-		if (savedLabels.indexOf(label) === -1) {
+	for (const label in labels) {
+		if (!savedLabels.includes(label)) {
 			throw new Error(
 				`Added label "${label}" is not included in initial labelset: ${util.inspect(
 					savedLabels,
 				)}`,
 			);
 		}
-	});
+	}
 };