Class Logger

A configurable logger class that supports different log levels and formatting.

Example

const logger = new Logger({ level: LogLevel.DEBUG, prefix: 'Langfuse SDK' });
logger.info('Application started');
logger.error('An error occurred', error);

Index

Constructors

constructor

Methods

debug error getLevel info isLevelEnabled setLevel warn

Constructors

constructor

new Logger(config?: LoggerConfig): Logger
Creates a new Logger instance.
Parameters
- config: LoggerConfig = ...
  Configuration options for the logger
Returns Logger
- Defined in packages/core/src/logger/index.ts:67

Methods

debug

debug(message: string, ...args: unknown[]): void
Logs a debug message.
Parameters
- message: string
  The debug message to log
- ...args: unknown[]
  Additional arguments to pass to console.debug
Returns void
- Defined in packages/core/src/logger/index.ts:143

error

error(message: string, ...args: unknown[]): void
Logs an error message.
Parameters
- message: string
  The error message to log
- ...args: unknown[]
  Additional arguments to pass to console.error
Returns void
- Defined in packages/core/src/logger/index.ts:107

getLevel

getLevel(): LogLevel
Gets the current log level.

Returns LogLevel
The current log level
- Defined in packages/core/src/logger/index.ts:163

info

info(message: string, ...args: unknown[]): void
Logs an informational message.
Parameters
- message: string
  The info message to log
- ...args: unknown[]
  Additional arguments to pass to console.info
Returns void
- Defined in packages/core/src/logger/index.ts:131

isLevelEnabled

isLevelEnabled(level: LogLevel): boolean
Checks if a given log level is enabled. Use this to guard expensive operations (like JSON.stringify) before debug logging.
Parameters
- level: LogLevel
  The log level to check
Returns boolean
True if the level is enabled, false otherwise
Example
```
if (logger.isLevelEnabled(LogLevel.DEBUG)) {
  logger.debug('Expensive data:', JSON.stringify(largeObject));
}
```
- Defined in packages/core/src/logger/index.ts:181

setLevel

setLevel(level: LogLevel): void
Sets the minimum log level.
Parameters
- level: LogLevel
  The new log level
Returns void
- Defined in packages/core/src/logger/index.ts:154

warn

warn(message: string, ...args: unknown[]): void
Logs a warning message.
Parameters
- message: string
  The warning message to log
- ...args: unknown[]
  Additional arguments to pass to console.warn
Returns void
- Defined in packages/core/src/logger/index.ts:119

Class Logger

Example

Index

Constructors

Methods

Constructors

constructor

Parameters

Returns Logger

Methods

debug

Parameters

Returns void

error

Parameters

Returns void

getLevel

Returns LogLevel

info

Parameters

Returns void

isLevelEnabled

Parameters

Returns boolean

Example

setLevel

Parameters

Returns void

warn

Parameters

Returns void

Settings

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