Logger

Type Alias: Logger

Logger = object

Defined in: types.ts:192

The logger interface.

Properties

addTransport

addTransport: (transport) => void

Defined in: types.ts:263

Add a transport at runtime. Affects this logger and its children.

Parameters

transport

Transport

Returns

void

---

child

child: {(context): Logger; (name, context?): Logger; }

Defined in: types.ts:237

Create a child logger.

• child(context) prepends a context object to every record.
• child(name) / child(name, context) nests a string scope (parent:child) that transports can render as a prefix — ideal for hierarchical CLI loggers (app, app:manifest).

Children share the parent’s transports (including any added later via addTransport) and inherit its level, timestamp format, and onTransportError.

Call Signature

(context): Logger

Parameters

context

Record<string, unknown>

Returns

Logger

Call Signature

(name, context?): Logger

Parameters

name

string

context?

Record<string, unknown>

Returns

Logger

---

debug

debug: (message, context?) => void

Defined in: types.ts:197

Parameters

message

string

context?

Record<string, unknown>

Returns

void

---

error

error: (messageOrError, context?) => void

Defined in: types.ts:204

Log an error. Pass an Error instance to capture name/message/stack/cause/code, or a message string with optional context.

Parameters

messageOrError

string | Error

context?

Record<string, unknown>

Returns

void

---

fatal

fatal: (messageOrError, context?) => void

Defined in: types.ts:205

Parameters

messageOrError

string | Error

context?

Record<string, unknown>

Returns

void

---

flush

flush: () => Promise<TransportStatus[]>

Defined in: types.ts:278

Flush all transports. Returns a per-transport status so callers can detect drains that failed (e.g. before exiting a serverless handler).

The promise always resolves; failures appear as { ok: false, error } entries in the returned array and are also reported via LoggerConfig.onTransportError if configured.

Returns

Promise<TransportStatus[]>

---

info

info: (message, context?) => void

Defined in: types.ts:198

Parameters

message

string

context?

Record<string, unknown>

Returns

void

---

isLevelEnabled

isLevelEnabled: (level) => boolean

Defined in: types.ts:194

Returns true if the given level would be emitted.

Parameters

level

LogLevel

Returns

boolean

---

log

log: (input) => void

Defined in: types.ts:223

Low-level structured log with full control over the record — including meta, kind, and args, which the convenience methods don’t expose. The escape hatch for wrappers that build their own entries.

Parameters

input

LogInput

Returns

void

Example

log.log({
  level: "info",
  message: "built %s in %dms",
  args: ["index.js", 12],
  kind: "success",
  meta: { entry: hostEntry },
});

---

mark

mark: (label, options?) => (extraContext?) => number

Defined in: types.ts:257

Start a performance marker. Returns a function that, when called, emits a record with durationMs measured from the start and returns that duration so callers can reuse the number.

The duration is returned even when the level is disabled (no record is emitted in that case).

Parameters

label

string

options?

level?

LogLevel

Returns

(extraContext?) => number

Example

const end = logger.mark("query.users");
const users = await db.users.find();
const ms = end({ count: users.length }); // logs, and ms is reusable

---

removeTransport

removeTransport: (name?) => number

Defined in: types.ts:268

Remove transports at runtime. With a name, removes every transport with that name; without one, removes all. Returns the number removed.

Parameters

name?

string

Returns

number

---

trace

trace: (message, context?) => void

Defined in: types.ts:196

Parameters

message

string

context?

Record<string, unknown>

Returns

void

---

warn

warn: (message, context?) => void

Defined in: types.ts:199

Parameters

message

string

context?

Record<string, unknown>

Returns

void