node_metrics_support

TypeScript metrics helper built on the official prom-client library.

import {
  CounterMetric,
  HistogramMetric,
  MetricsExporter,
  MetricsRegistry,
} from 'node_metrics_support';

MetricsRegistry.configure({ prefix: 'orders' });
CounterMetric.counter('requests', { method: 'GET', route: '/orders' }).inc();
HistogramMetric.histogram('response_seconds', { route: '/orders' }).observe(0.12);

const prometheus = await MetricsExporter.toPrometheus();
const json = await MetricsExporter.toJsonString();

All metric classes share the registry configured through MetricsRegistry. For NestJS, add PrometheusController as a controller. It exposes GET /api/metrics and GET /api/metrics-json.

CounterMetric, GaugeMetric, SummaryMetric, HistogramMetric, and Timer provide the metric APIs. Summary quantiles and histogram bucket configuration are supplied by trailing arguments to summary and histogram. Timers are curried: Timer.time('work', { operation: 'sync' })(() => doWork()). Class methods can be annotated: @timer('work'). Scrape-time gauges are curried: GaugeMetric.gaugeOnScrape('queue_depth', { queue: 'mail' })(() => currentDepth).