Class BrowserLogger

Turn tracking off: tracked functions become plain pass-through calls

Disable memory usage tracking

Disable silent mode (allow console output)

Turn tracking on

Enable memory usage tracking

Enable silent mode (no console output)

Statistics as a text table, slowest total first

Per-label statistics (ms): count, errors, total, mean, min, max, p50/p95/p99 and mean self time.

Per-label statistics (ms): count, errors, total, mean, min, max, p50/p95/p99 and mean self time.

Get the current tracking mode

Whether tracking is on

Call listener with every finished top-level execution tree (even when silent or below threshold). Returns an unsubscribe function.

Call listener for every finished call (nested ones included) that took at least threshold ms. Pass a number, or per-label thresholds with an optional '*' default:

tp.onSlow(200, (call, root) => logger.warn(${call.label} took ${call.duration}ms in ${root.label})); tp.onSlow({ 'db.query': 50, 'GET /search': 500, '*': 1000 }, alert);

Works in every tracking mode and when silent. Returns an unsubscribe function.

Print the statistics table to the console

Register a module for tracking

Reset the tracker state (in-flight executions and statistics)

Clear collected statistics

Set configuration options

Set the sampling rate

Start a manually-ended execution (a span), e.g. for a request:

const span = tp.start('GET /users'); span.run(() => next()); // tracked calls inside become children res.on('finish', () => span.end());

Start recording finished calls for a Chrome/Perfetto trace.

const recording = tp.startTrace(); await work(); fs.writeFileSync('trace.json', JSON.stringify(recording.stop()));

Open the file in https://ui.perfetto.dev or chrome://tracing.

Method decorator. Works with TypeScript 5 / TC39 standard decorators and with legacy experimentalDecorators. The label defaults to "ClassName.method".

class UserService { @tp.traced() async getUser(id: string) { ... } }

Track a function execution

Track every method of an object or class instance, including methods inherited from its prototype, without copying it. Returns a proxy: state changes go to the original object, and methods run with the original object as this (so private #fields keep working).

Register a plugin (exporter, custom sink). Returns an unsubscribe function.