Reference

Configuration

LoggerOptions and the fluent LoggerConfiguration.

Two spellings of the same thing. The options object is the JavaScript one; the fluent builder is Serilog's. createLogger() makes an independent logger; configure() reconfigures the global log in place, and every logger derived from it follows.

`LoggerOptions`#

configure({
  minimumLevel: 'info',
  overrides: { next: 'warn', 'app.db': 'verbose' },
  sinks: [consoleSink()],
  auditSinks: [],
  enrichers: [withProperty('Application', 'shop')],
  filters: [byExcluding(Matching.fromSource('health'))],
  destructuring: { maxDepth: 10, redact: ['password'] },
  properties: { Version: '1.4.0' },
  logContext: true,
  onSinkError: (error, sink, event) => { … },
});

Option	Type	Default
`minimumLevel`	`LogLevel \| string \| LevelSwitch`	`'info'`, or `LOGIT_LEVEL`	events below it are dropped before capture
`overrides`	`Record<string, LogLevel \| string \| LevelSwitch>`	`{}` + `LOGIT_OVERRIDES`	per-`SourceContext` prefix, longest match wins
`sinks`	`Sink[]`	`[consoleSink()]` when neither `sinks` nor `auditSinks` is given	where events go; a `Logger` is a sink
`auditSinks`	`Sink[]`	`[]`	sinks whose failure throws from the logging call
`enrichers`	`Enricher[]`	`[]`	run in order, after the context enricher
`filters`	`Filter[]`	`[]`	all must return `true`
`destructuring`	`Partial<DestructuringOptions>`	see below	the capture rules
`properties`	`Record<string, unknown>`	—	fixed properties; shorthand for `withProperties()`
`logContext`	`boolean`	`true`	include `fromLogContext()`
`onSinkError`	`(error, sink, event) => void`	`selfLog`	where a non-audit sink's failure goes

`DestructuringOptions`#

Option	Default
`maxDepth`	`10`	deeper values become `'[Object]'` / `'[Array]'`
`maxStringLength`	`Infinity`	longer strings are cut with `…`
`maxCollectionCount`	`Infinity`	arrays, Sets and Maps are cut
`redact`	`[]`	keys / dotted paths whose values are replaced
`redactedValue`	`'[Redacted]'`
`policies`	`[]`	`DestructuringPolicy[]`, first answer wins
`typeTag`	`true`	write `$type` for destructured class instances

See Structured data and Redaction.

`LoggerConfiguration`#

import { LoggerConfiguration, configure, Matching } from '@unhingged/logit';

const logger = new LoggerConfiguration()
  .minimumLevel.debug()
  .minimumLevel.override('next', 'warn')
  .enrich.withProperty('Application', 'shop')
  .filter.byExcluding(Matching.fromSource('health'))
  .destructure.redact('password')
  .writeTo.console()
  .writeTo.seq({ serverUrl: 'http://localhost:5341' }, )
  .createLogger();

configure(new LoggerConfiguration().minimumLevel.info().writeTo.console()); // the global, from a builder

Every method returns the configuration, so calls chain.

Group	Methods
`minimumLevel`	`verbose()` `debug()` `info()` / `information()` `warn()` / `warning()` `error()` `fatal()` · `is(level)` · `controlledBy(levelSwitch)` · `override(source, level)`
`writeTo`	`sink(...sinks)` · `console(options?)` · `stream(stream, options?)` · `http(options)` · `seq(options)` · `logger(configure, restrictedToMinimumLevel?)` — a sub-logger
`auditTo`	`sink(...sinks)`
`enrich`	`with(...enrichers)` · `fromLogContext()` · `withProperty(name, value, destructure?)` · `withProperties(object, destructure?)`
`filter`	`with(...filters)` · `byExcluding(pred)` · `byIncludingOnly(pred)`
`destructure`	`toMaximumDepth(n)` · `toMaximumStringLength(n)` · `toMaximumCollectionCount(n)` · `with(...policies)` · `byTransforming(Type, fn)` · `redact(...keys)`
`readFrom`	`env()` — `LOGIT_LEVEL` / `LOGIT_OVERRIDES` are read by default; this makes it explicit
—	`withoutLogContext()` · `toOptions()` → `LoggerOptions` · `createLogger()` → `Logger`

The file sink and the OpenTelemetry sinks live in their own entries and are added with .writeTo.sink(fileSink({ … })).

Defaults, in one place#


minimum level	`info`
sinks	one console sink: pretty on a terminal or in a browser, JSON lines elsewhere
context	`fromLogContext()` on
destructuring	depth 10, no string / collection limits, no redaction, `$type` on
selfLog	off

Configuration

LoggerOptions#

DestructuringOptions#

LoggerConfiguration#

Defaults, in one place#

`LoggerOptions`#

`DestructuringOptions`#

`LoggerConfiguration`#