This is the default logger. It will output color coded log messages to the console via console.log().

This handler will output to a file using an optional mode (default is a, e.g. append). The file will grow indefinitely. It uses a buffer for writing to file. Logs can be manually flushed with fileHandler.flush(). Log messages with a log level greater than error are immediately flushed. Logs are also flushed on process completion.

Takes an input date and a formatString to format to a string.