Type Alias: Metrics

Metrics = Record<string, number>

Defined in: packages/utils/src/metrics.ts:55

Simple metrics collector for performance testing.

A plain object where keys are metric names and values are counts, bytes, or timers (milliseconds). This flexible structure allows tracking arbitrary metrics without defining them upfront.

Unified Metrics (cross-transport)

These metrics work consistently across HTTP and WebSocket transports:

• roundTrips: Number of network round trips (HTTP requests or WebSocket message pairs)
• payloadBytesSent: Total payload bytes sent
• payloadBytesReceived: Total payload bytes received

Transport-Specific Metrics

These provide additional detail for specific transports:

• httpRequests: HTTP request count
• wsUpgradeRequests: WebSocket connection establishment count
• wsSentMessages: WebSocket messages sent count
• wsReceivedMessages: WebSocket messages received count
• wsSentPayloadBytes: WebSocket payload bytes sent (deprecated - use payloadBytesSent)
• wsReceivedPayloadBytes: WebSocket payload bytes received (deprecated - use payloadBytesReceived)

Example

const metrics: Metrics = {};

// Unified metrics (work for both HTTP and WebSocket)
metrics.roundTrips = (metrics.roundTrips ?? 0) + 1;
metrics.payloadBytesSent = (metrics.payloadBytesSent ?? 0) + bytes;
metrics.payloadBytesReceived = (metrics.payloadBytesReceived ?? 0) + bytes;

// Transport-specific metrics
metrics.httpRequests = (metrics.httpRequests ?? 0) + 1;
metrics.wsUpgradeRequests = (metrics.wsUpgradeRequests ?? 0) + 1;
metrics.wsSentMessages = (metrics.wsSentMessages ?? 0) + 1;
metrics.wsReceivedMessages = (metrics.wsReceivedMessages ?? 0) + 1;

// Track timers (milliseconds)
const start = performance.now();
// ... do work ...
metrics.totalDuration = performance.now() - start;

console.log(metrics);
// { 
//   roundTrips: 52,
//   payloadBytesSent: 12847,
//   payloadBytesReceived: 11203,
//   httpRequests: 5, 
//   wsUpgradeRequests: 2, 
//   wsSentMessages: 47,
//   wsReceivedMessages: 47,
//   totalDuration: 234.5 
// }