bug: support array argument to labels() again

This was undocumented and untested, and broke in 13.1.0.

Fixes #499

Author: zbjornson

CHANGELOG.md

@@ -17,6 +17,8 @@ project adheres to [Semantic Versioning](http://semver.org/).
   avoid failures from the server when using `Content-Encoding: gzip` header.
 - Refactor `escapeString` helper in `lib/registry.js` to improve performance and
   avoid an unnecessarily complex regex.
+- Support array argument to `metric.labels()`. This was supported prior to
+  version 13.1 (undocumented). [#553](https://github.com/siimon/prom-client/pull/553)
 
 ### Added
 

README.md

@@ -315,6 +315,8 @@ gauge.set({ method: 'GET', statusCode: '200' }, 100);
 gauge.labels({ method: 'GET', statusCode: '200' }).set(100);
 // 3rd version: And again the same effect as above
 gauge.labels('GET', '200').set(100);
+// 4th version: And again the same effect as above
+gauge.labels(['GET', '200']).set(100);
 ```
 
 It is also possible to use timers with labels, both before and after the timer

index.d.ts

@@ -258,6 +258,13 @@ export class Counter<T extends string = string> {
 	 */
 	get(): Promise<MetricObjectWithValues<MetricValue<T>>>;
 
+	/**
+	 * Return the child for given labels
+	 * @param values Label values
+	 * @return Configured counter with given labels
+	 */
+	labels(values: string[]): Counter.Internal;
+
 	/**
 	 * Return the child for given labels
 	 * @param values Label values
@@ -277,6 +284,12 @@ export class Counter<T extends string = string> {
 	 */
 	reset(): void;
 
+	/**
+	 * Remove metrics for the given label values
+	 * @param values Label values
+	 */
+	remove(values: string[]): void;
+
 	/**
 	 * Remove metrics for the given label values
 	 * @param values Label values
@@ -373,6 +386,13 @@ export class Gauge<T extends string = string> {
 	 */
 	startTimer(labels?: LabelValues<T>): (labels?: LabelValues<T>) => number;
 
+	/**
+	 * Return the child for given labels
+	 * @param values Label values
+	 * @return Configured gauge with given labels
+	 */
+	labels(values: string[]): Gauge.Internal<T>;
+
 	/**
 	 * Return the child for given labels
 	 * @param values Label values
@@ -392,6 +412,12 @@ export class Gauge<T extends string = string> {
 	 */
 	reset(): void;
 
+	/**
+	 * Remove metrics for the given label values
+	 * @param values Label values
+	 */
+	remove(values: string[]): void;
+
 	/**
 	 * Remove metrics for the given label values
 	 * @param values Label values
@@ -497,6 +523,13 @@ export class Histogram<T extends string = string> {
 	 */
 	zero(labels: LabelValues<T>): void;
 
+	/**
+	 * Return the child for given labels
+	 * @param values Label values
+	 * @return Configured histogram with given labels
+	 */
+	labels(values: string[]): Histogram.Internal<T>;
+
 	/**
 	 * Return the child for given labels
 	 * @param values Label values
@@ -511,6 +544,12 @@ export class Histogram<T extends string = string> {
 	 */
 	labels(labels: LabelValues<T>): Histogram.Internal<T>;
 
+	/**
+	 * Remove metrics for the given label values
+	 * @param values Label values
+	 */
+	remove(values: string[]): void;
+
 	/**
 	 * Remove metrics for the given label values
 	 * @param values Label values
@@ -598,6 +637,13 @@ export class Summary<T extends string = string> {
 	 */
 	reset(): void;
 
+	/**
+	 * Return the child for given labels
+	 * @param values Label values
+	 * @return Configured summary with given labels
+	 */
+	labels(values: string[]): Summary.Internal<T>;
+
 	/**
 	 * Return the child for given labels
 	 * @param values Label values
@@ -612,6 +658,12 @@ export class Summary<T extends string = string> {
 	 */
 	labels(labels: LabelValues<T>): Summary.Internal<T>;
 
+	/**
+	 * Remove metrics for the given label values
+	 * @param values Label values
+	 */
+	remove(values: string[]): void;
+
 	/**
 	 * Remove metrics for the given label values
 	 * @param values Label values

lib/util.js

@@ -44,7 +44,7 @@ exports.setValueDelta = function setValueDelta(
 };
 
 exports.getLabels = function (labelNames, args) {
-	if (typeof args[0] === 'object') {
+	if (typeof args[0] === 'object' && !Array.isArray(args[0])) {
 		return args[0];
 	}
 

test/gaugeTest.js

@@ -162,6 +162,13 @@ describe.each([
 				it('should handle labels provided as an object', async () => {
 					instance.labels({ code: '200' }).inc();
 
+					const values = (await instance.get()).values;
+					expect(values).toHaveLength(1);
+					expect(values[0].labels).toEqual({ code: '200' });
+				});
+				it('should handle labels provided as an array', async () => {
+					instance.labels([200]).inc();
+
 					const values = (await instance.get()).values;
 					expect(values).toHaveLength(1);
 					expect(values[0].labels).toEqual({ code: '200' });