Can I extend the console object (to redirect logging) in javascript?

Question

Can I extend the console object?

I tried something like:

Console.prototype.log = function(msg){ Console.prototype.log.call(msg); alert(msg); } 

But that did not work. I want to add an additional entry to the console object through a framework such as log4javascript and still use the standard console object (in cases where log4javascript is not available) in my code.

Thanks in advance!

Answer 1

Try the following:

 (function() { var exLog = console.log; console.log = function(msg) { exLog.apply(this, arguments); alert(msg); } })() 

Answer 2

Use a proxy template, see my answer for a similar case:

JavaScript: warning override ()

Hope this helps

Answer 3

You can also add log time in this way:

Moments added or use New Date () instead of a moment.

 var oldConsole = console.log; console.log = function(){ var timestamp = "[" + moment().format("YYYY-MM-DD HH:mm:ss:SSS") + "] "; Array.prototype.unshift.call(arguments, timestamp); oldConsole.apply(this, arguments); }; 

Answer 4

 // console aliases and verbose logger - console doesnt prototype var c = console; cl = c.log, ce = c.error, cv = c.verbose = function() { if (!myclass || !myclass.verbose) // verbose switch return; var args = Array.prototype.slice.call(arguments); // toArray args.unshift('Verbose:'); clapply(this, args); // log }; // you can then do var myclass = new myClass(); myclass.prototype.verbose = false; // generally these calls would be inside your class cv('1 This will NOT log as verbose == false'); cl('2 This will log'); myclass.verbose = true; cv('3 This will log'); 

I noticed that the above use of Array.prototype.unshift.call by nitesh is the best way to add the tag "Verbose:".

Answer 5

This is really the same as some others have given, but I think this is the most elegant and least hacker way to achieve this. The propagation syntax (... args) ensures that no arguments are lost .

 var _console={...console} console.log = function(...args) { var msg = {...args}[0]; //YOUR_CODE _console.log(...args); }