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A very simple logging library for node.js


  • Supports the %s format string - use it for every argument. If the parameter is not a string, it is converted to one using String(object)

  • Prints:

    • Timestamp
    • Log Statement Severity
    • Module Name
    • Constructor name
    • Function name
    • Line number
  • A logger object (returned by getLogger) supports the following methods:

    • trace
    • debug
    • info
    • warn
    • error
    • fatal
    • getLevel(): Returns the currently set log level
    • setLevel(levelString): Sets the current log level
  • trace is the most verbose log level and fatal is the least. If you set the log level to info, then all log statements between levels fatal and info (both inclusive) will be logged.

Example usage

var path     = require('path');
var filename = path.basename(path.normalize(__filename))
var log      = require('node-lumberjack').getLogger(filename, 'trace');"Line 1");
log.warn("Line %s", 2);

See the file test.js for a complete example on how to use this library.

Example output

[2012-06-10 12:14:23.350] [INFO] [test.js:test:7] - Line 1
[2012-06-10 12:14:23.359] [WARN] [test.js:test:8] - Line 2
[2012-06-10 12:14:23.359] [DEBUG] [test.js:test:9] - 3rd line
[2012-06-10 12:14:23.360] [ERROR] [test.js:test:10] - 4th Line comes here
[2012-06-10 12:14:23.360] [TRACE] [test.js:test:11] - Tracing on the 5th line

node-lumberjack prints the module name, constructor name, function name and the line number on which the logging function was called. Here is an example:

[2012-06-10 12:14:23.362] [TRACE] [test.js:CtorName.functionName:20] - You should see the object & function name on this line