Logging for JavaScript
Why ?
When you're writing some JavaScript you can miss something : a logging tool. A way to do logging with Javascript (you used it...) is to use alert(msg) Window object's method ; alert logging can quickly be very annoying when debugging some code in a for statement...
There were already some library like log4js or fvlogger (thanks for colors and icons) when I wrote this script but they were not exactly how I wanted the tool to be ; quickly :
- with fvlogger, you must declare your output "window" in your document
- fvloger defines to much window scope functions (giving more chance to duplicate function name in your document)
- log4js was good but didn't declare any
is<Level>Enabled()like methods (althought it is possible to test aLoginstance threshold) to minimize log impact on script in production use . - I like to write such things ;o)
How ?
The script appends paragraph elements to a HTMLElement container identified by id attribute value LogWindow (you can also customize it setting Log.ContainerId variable value). If the container does not exists, it is created.
Usage is simple :
...
Log.setThreshold("debug"); // somewhere in an 'init()' function
...
Log.debug("Some message required to debug");
if (Log.isDebugEnabled()) {
Log.debug("Some debug message that could have more impact on code execution "+object.heavyToStringMethod());
}
...Tested with :
- Firefox 1.5.0.4
- IE 6.0.2800.1106.xpsp2.050301-1526
Example
Click on the 'launch ...' links above.
- Launch testLogs() [show function],
- Launch requiredParamScript() [show function],
- Launch buggyScript() [show function].
written with vim.