fix: include the metric and label names in deprecation warning (#114)

Author: wkillerud

lib/index.js

@@ -21,15 +21,16 @@ const metricTypes = {
 	SUMMARY: "summary",
 };
 
-function deprecateMetaForLabels() {
+function deprecateMetaForLabels(metric, label) {
 	if (!deprecateMetaForLabels.warned) {
 		deprecateMetaForLabels.warned = true;
 		process.emitWarning(
-			`
+			`Got label ${label} for metric ${metric} using the meta property.
+
 Using metric meta property for labels (eg. metric({ meta: { label: "value" } })) is now deprecated and will be removed in a future version.
-Please use the "labels" key instead.
-See https://github.com/metrics-js/client for up to date usage.
-            `,
+Please use the labels key instead (eg metric({ labels: { label: "value" } })).
+
+See https://github.com/metrics-js/client for up to date usage.`,
 			"DeprecationWarning",
 		);
 	}
@@ -90,7 +91,7 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
 				if (key === "buckets") return;
 				if (key === "quantiles") return;
 
-				deprecateMetaForLabels();
+				deprecateMetaForLabels(metric.name, key);
 
 				labelNames.push(key);
 				labelValues.push(metric.meta[key]);