# Yahoo! UI Library

### Logger Widget 2.8.1

Yahoo! UI Library > logger > YAHOO.widget.Logger
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## `static` Class YAHOO.widget.Logger

The singleton Logger class provides core log management functionality. Saves logs written through the global YAHOO.log function or written by a LogWriter instance. Provides access to logs for reading by a LogReader instance or native browser console such as the Firebug extension to Firefox or Safari's JavaScript console through integration with the console.log() method.

### Properties

#### _browserConsoleEnabled - `private static Boolean`

Internal property to track whether output to browser console is enabled.
Default Value: false

#### _lastTime - `private static Date`

Timestamp of last logged message.

#### _stack - `private static Array`

Array to hold all log messages.

#### _startTime - `private static Date`

Static timestamp of Logger initialization.

#### categories - `static String[]`

Array of categories.
Default Value: ["info","warn","error","time","window"]

#### loggerEnabled - `static Boolean`

True if Logger is enabled, false otherwise.
Default Value: true

#### maxStackEntries - `static Number`

Upper limit on size of internal stack.
Default Value: 2500

#### sources - `static String[]`

Array of sources.
Default Value: ["global"]

### Methods

#### _createNewCategory

`private void _createNewCategory ( sCategory )`
Creates a new category of log messages and fires categoryCreateEvent.

Parameters:
  `sCategory <String>` Category name.

#### _createNewSource

`private void _createNewSource ( sSource )`
Creates a new source of log messages and fires sourceCreateEvent.

Parameters:
  `sSource <String>` Source name.

#### _isNewCategory

`private Boolean _isNewCategory ( sCategory )`
Checks to see if a category has already been created.

Parameters:
  `sCategory <String>` Category name.

Returns: `Boolean`
  Returns true if category is unknown, else returns false.

#### _isNewSource

`private Boolean _isNewSource ( sSource )`
Checks to see if a source already exists.

Parameters:
  `sSource <String>` Source name.

Returns: `Boolean`
  Returns true if source is unknown, else returns false.

#### _onWindowError

`private void _onWindowError ( sMsg , sUrl , sLine )`
Handles logging of messages due to window error events.

Parameters:
  `sMsg <String>` The error message.
  `sUrl <String>` URL of the error.
  `sLine <String>` Line number of the error.

#### _printToBrowserConsole

`private void _printToBrowserConsole ( oEntry )`
Outputs a log message to global console.log() function.

Parameters:
  `oEntry <Object>` Log entry object.

#### disableBrowserConsole

`void disableBrowserConsole ( )`
Disables output to the browser's global console.log() function, which is used by the Firebug extension to Firefox as well as Safari.

#### enableBrowserConsole

`void enableBrowserConsole ( )`
Enables output to the browser's global console.log() function, which is used by the Firebug extension to Firefox as well as Safari.

#### getStack

`Object[] getStack ( )`
Public accessor to internal stack of log message objects.

Returns: `Object[]`
  Array of log message objects.

#### getStartTime

`Date getStartTime ( )`
Public accessor to internal start time.

Returns: `Date`
  Internal date of when Logger singleton was initialized.

#### handleWindowErrors

`void handleWindowErrors ( )`
Surpresses native JavaScript errors and outputs to console. By default, Logger does not handle JavaScript window error events. NB: Not all browsers support the window.onerror event.

#### log

`void log ( sMsg , sCategory , sSource )`
Saves a log message to the stack and fires newLogEvent. If the log message is assigned to an unknown category, creates a new category. If the log message is from an unknown source, creates a new source. If browser console is enabled, outputs the log message to browser console.

Parameters:
  `sMsg <String>` The log message.
  `sCategory <String>` Category of log message, or null.
  `sSource <String>` Source of LogWriter, or null if global.

#### reset

`void reset ( )`
Resets internal stack and startTime, enables Logger, and fires logResetEvent.

#### unhandleWindowErrors

`void unhandleWindowErrors ( )`
Unsurpresses native JavaScript errors. By default, Logger does not handle JavaScript window error events. NB: Not all browsers support the window.onerror event.

### Events

#### categoryCreateEvent

`categoryCreateEvent ( sCategory )`
Fired when a new category has been created.

Parameters:
  `sCategory <String>` Category name.

#### logResetEvent

`logResetEvent ( )`
Fired when the Logger has been reset has been created.

#### newLogEvent

`newLogEvent ( sMsg )`
Fired when a new log message has been created.

Parameters:
  `sMsg <String>` Log message.

#### sourceCreateEvent

`sourceCreateEvent ( sSource )`
Fired when a new source has been named.

Parameters:
  `sSource <String>` Source name.

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