loglevel

property levels

readonly levels: LogLevel;

• Available log levels.

property methodFactory

methodFactory: MethodFactory;

• Plugin API entry point. This will be called for each enabled method each time the level is set (including initially), and should return a MethodFactory to be used for the given log method, at the given level, for a logger with the given name. If you'd like to retain all the reliability and features of loglevel, it's recommended that this wraps the initially provided value of log.methodFactory

method debug

debug: (...msg: any[]) => void;

• Output debug message to console including appropriate icons

  Parameter msg

  any data to log to the console

method disableAll

disableAll: (persist?: boolean) => void;

• This disables all log messages, and is equivalent to log.setLevel("silent").

  Parameter persist

  Where possible the log level will be persisted. LocalStorage will be used if available, falling back to cookies if not. If neither is available in the current environment (i.e. in Node), or if you pass false as the optional 'persist' second argument, persistence will be skipped.

method enableAll

enableAll: (persist?: boolean) => void;

• This enables all log messages, and is equivalent to log.setLevel("trace").

  Parameter persist

  Where possible the log level will be persisted. LocalStorage will be used if available, falling back to cookies if not. If neither is available in the current environment (i.e. in Node), or if you pass false as the optional 'persist' second argument, persistence will be skipped.

method error

error: (...msg: any[]) => void;

• Output error message to console including appropriate icons

  Parameter msg

  any data to log to the console

method getLevel

getLevel: () => LogLevel[keyof LogLevel];

• Returns the current logging level, as a value from LogLevel. It's very unlikely you'll need to use this for normal application logging; it's provided partly to help plugin development, and partly to let you optimize logging code as below, where debug data is only generated if the level is set such that it'll actually be logged. This probably doesn't affect you, unless you've run profiling on your code and you have hard numbers telling you that your log data generation is a real performance problem.

method info

info: (...msg: any[]) => void;

• Output info message to console including appropriate icons

  Parameter msg

  any data to log to the console

method log

log: (...msg: any[]) => void;

• Output debug message to console including appropriate icons

  Parameter msg

  any data to log to the console

method rebuild

rebuild: () => void;

• Rebuild the logging methods on this logger and its child loggers.

  This is mostly intended for plugin developers, but can be useful if you update a logger's methodFactory or if you want to apply the root logger’s level to any *pre-existing* child loggers (this updates the level on any child logger that hasn't used setLevel() or setDefaultLevel()).

method resetLevel

resetLevel: () => void;

• This resets the current log level to the default level (or warn if no explicit default was set) and clears the persisted level if one was previously persisted.

method setDefaultLevel

setDefaultLevel: (level: LogLevelDesc) => void;

• This sets the current log level only if one has not been persisted and can’t be loaded. This is useful when initializing scripts; if a developer or user has previously called setLevel(), this won’t alter their settings. For example, your application might set the log level to error in a production environment, but when debugging an issue, you might call setLevel("trace") on the console to see all the logs. If that error setting was set using setDefaultLevel(), it will still say as trace on subsequent page loads and refreshes instead of resetting to error.

  The level argument takes is the same values that you might pass to setLevel(). Levels set using setDefaultLevel() never persist to subsequent page loads.

  Parameter level

  as a string, like 'error' (case-insensitive) or as a number from 0 to 5 (or as log.levels. values)

method setLevel

setLevel: (level: LogLevelDesc, persist?: boolean) => void;

• This disables all logging below the given level, so that after a log.setLevel("warn") call log.warn("something") or log.error("something") will output messages, but log.info("something") will not.

  Parameter level

  as a string, like 'error' (case-insensitive) or as a number from 0 to 5 (or as log.levels. values)

  Parameter persist

  Where possible the log level will be persisted. LocalStorage will be used if available, falling back to cookies if not. If neither is available in the current environment (i.e. in Node), or if you pass false as the optional 'persist' second argument, persistence will be skipped.

method trace

trace: (...msg: any[]) => void;

• Output trace message to console. This will also include a full stack trace

  Parameter msg

  any data to log to the console

method warn

warn: (...msg: any[]) => void;

• Output warn message to console including appropriate icons

  Parameter msg

  any data to log to the console

property DEBUG

DEBUG: 1;

property ERROR

ERROR: 4;

property INFO

INFO: 2;

property SILENT

SILENT: 5;

property TRACE

TRACE: 0;

property WARN

WARN: 3;

property default

default: RootLogger;

• A .default property for ES6 default import compatibility

method getLogger

getLogger: (name: string | symbol) => Logger;

• This gets you a new logger object that works exactly like the root log object, but can have its level and logging methods set independently. All loggers must have a name (which is a non-empty string or a symbol) Calling * getLogger() multiple times with the same name will return an identical logger object. In large applications, it can be incredibly useful to turn logging on and off for particular modules as you are working with them. Using the getLogger() method lets you create a separate logger for each part of your application with its own logging level. Likewise, for small, independent modules, using a named logger instead of the default root logger allows developers using your module to selectively turn on deep, trace-level logging when trying to debug problems, while logging only errors or silencing logging altogether under normal circumstances.

  Parameter name

  The name of the produced logger

method getLoggers

getLoggers: () => { [name: string]: Logger };

• This will return you the dictionary of all loggers created with getLogger, keyed off of their names.

method noConflict

noConflict: () => any;

• If you're using another JavaScript library that exposes a 'log' global, you can run into conflicts with loglevel. Similarly to jQuery, you can solve this by putting loglevel into no-conflict mode immediately after it is loaded onto the page. This resets to 'log' global to its value before loglevel was loaded (typically undefined), and returns the loglevel object, which you can then bind to another name yourself.