debugout.js

(debug output) generates a text file from your logs that can be searched, timestamped, downloaded and more. See some examples below.

Debugout's log() accepts any type of object including functions. Debugout is not a monkey patch, but a separate logging class altogether that you use instead of console.

Some highlights of debugout:

• get the entire log, or the tail at run-time or any time
• search and slice the log
• better understand usage patterns with optional timestamps
• toggle live logging (console.log) in one place
• optionally store the output in window.localStorage and continuously add to the same log each session
• optionally cap the log to X most recent lines to limit memory consumption

Try the demo

Installation

Simply include the debugout.js file in your project or install via a package manager:

npm: npm install debugout.js

bower: bower install debugout.js

Usage

Create a new debugout object in the global namespace, at the top of your script, and replace all your console log methods with debugout's log method:

var bugout = new debugout();

// instead of console.log('some object or string')
bugout.log('some object or string');

Whatever you log is saved and added to the log file on a new line.

Methods

• log() - like console.log(), but saved!
• getLog() - returns the entire log.
• tail(numLines) - returns the last X lines of the log, where X is the number you pass. Defaults to 100.
• search(string) - returns numbered lines where there were matches for your search. Pass a string.
• getSlice(start, numLines) - get a 'slice' of the log. Pass the starting line and how many lines after it you want
• downloadLog() - downloads a .txt file of the log. See example below.
• clear() - clears the log.
• determineType() - a more granular version of typeof for your convenience

Options

In the debugout function definition, you can edit options:

// log in real time (forwards to console.log)
self.realTimeLoggingOn = true; 
// insert a timestamp in front of each log
self.useTimestamps = false; 
// store the output using window.localStorage() and continuously add to the same log each session
self.useLocalStorage = false; 
// set to false after you're done debugging to avoid the log eating up memory
self.recordLogs = true; 
// to avoid the log eating up potentially endless memory
self.autoTrim = true; 
// if autoTrim is true, this many most recent lines are saved
self.maxLines = 2500; 
// how many lines tail() will retrieve
self.tailNumLines = 100; 
// filename of log downloaded with downloadLog()
self.logFilename = 'log.txt';
// max recursion depth for logged objects
self.maxDepth = 25;

Outputting examples

Here are a couple examples of what you can do with the log. Each example assumes that you have established a debugout object and are logging with it:

var bugout = new debugout();
bugout.log('something');
bugout.log(somethingElse);
bugout.log('etc');

Example #1: Button that downloads the log as a .txt file

Simply call debugout's downloadLog() method. You can change the filename by editing self.logFilename.

<input type="button" value="Download log" onClick="bugout.downloadLog()">

Example #2: PhoneGap app that attaches the log to an email

Example shown uses the Email Composer plugin and also requires the File plugin: cordova plugin add org.apache.cordova.file.

function sendLog() {
	var logFile = bugout.getLog();

	// save the file locally, so it can be retrieved from emailComposer
	window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function(fileSystem) {
		// create the file if it doesn't exist
		fileSystem.root.getFile('log.txt', {create: true, exclusive: false}, function(file) {
			// create writer
			file.createWriter(function(writer) {
		        // write
	    		writer.write(logFile);
	    		// when done writing, call up email composer
				writer.onwriteend = function(evt) {
		            // params: subject,body,toRecipients,ccRecipients,bccRecipients,bIsHTML,attachments,filename
		            var subject = 'Log from myApp';
		            var body = 'Attached is a log from my recent testing session.';
					window.plugins.emailComposer.showEmailComposer(subject,body,[],[],[],false,['log.txt'], ['myApp log']);
		        }
			}, fileSystemError);
		}, fileSystemError);
	}, fileSystemError);
}
function fileSystemError(error) {
    bugout.log('Error getting file system: '+error.code);
}

And more...

• Post the log to your server via an ajax request if an error or some other event occurs.
• Allow the user to download a copy of a submitted form.
• Generate a receipt for the user to download.
• Record survey answers and know how long each question took the user to answer.