A counter is a cumulative metric that represents a single numerical value that only ever goes up

A gauge is a metric that represents a single numerical value that can arbitrarily go up and down.

A histogram samples observations (usually things like request durations or response sizes) and counts them in configurable buckets

Push metrics to a Pushgateway

Container for all registered metrics

A summary samples observations

The Content-Type of the metrics for use in the response headers.

The register that contains all metrics

Configure default metrics

Create an array that grows exponentially

Create an array with equal spacing between the elements

Validate a metric name

Aggregation methods, used for aggregating metrics in a Node.js cluster.

General metric type