How to quickly and conveniently disable all console.log statements in my code?

Question

Is there any way to turn off all console.log statements in my JavaScript code, for testing purposes?

Answer 1

I have used winston logger earlier.

Nowadays I am using below simpler code from experience:

1. Set the environment variable from cmd/ command line (on Windows):

   cmd
   setx LOG_LEVEL info
   

Or, you could have a variable in your code if you like, but above is better.

2. Restart cmd/ command line, or, IDE/ editor like Netbeans

3. Have below like code:

   console.debug = console.log;   // define debug function
   console.silly = console.log;   // define silly function
   
   switch (process.env.LOG_LEVEL) {
       case 'debug':
       case 'silly':
           // print everything
           break;
   
       case 'dir':
       case 'log':
           console.debug = function () {};
           console.silly = function () {};
           break;
   
       case 'info':
           console.debug = function () {};
           console.silly = function () {};
           console.dir = function () {};
           console.log = function () {};
           break;
   
       case 'trace':   // similar to error, both may print stack trace/ frames
       case 'warn':    // since warn() function is an alias for error()
       case 'error':
           console.debug = function () {};
           console.silly = function () {};
           console.dir = function () {};
           console.log = function () {};
           console.info = function () {};
           break;
   }
   

4. Now use all console.* as below:

   console.error(' this is a error message '); // will print
   console.warn(' this is a warn message '); // will print
   console.trace(' this is a trace message '); // will print
   console.info(' this is a info message '); // will print, LOG_LEVEL is set to this
   
   console.log(' this is a log message '); // will NOT print
   console.dir(' this is a dir message '); // will NOT print
   console.silly(' this is a silly message '); // will NOT print
   console.debug(' this is a debug message '); // will NOT print
   

Now, based on your LOG_LEVEL settings made in the point 1 (like, setx LOG_LEVEL log and restart command line), some of the above will print, others won't print

Hope that helped.

Answer 2

I know you asked how to disable console.log, but this might be what you're really after. This way you don't have to explicitly enable or disable the console. It simply prevents those pesky console errors for people who don't have it open or installed.

if(typeof(console) === 'undefined') {
    var console = {};
    console.log = console.error = console.info = console.debug = console.warn = console.trace = console.dir = console.dirxml = console.group = console.groupEnd = console.time = console.timeEnd = console.assert = console.profile = function() {};
}

Answer 3

Just change the flag DEBUG to override the console.log function. This should do the trick.

var DEBUG = false;
// ENABLE/DISABLE Console Logs
if(!DEBUG){
  console.log = function() {}
}

Answer 4

This a hybrid of answers from SolutionYogi and Chris S. It maintains the console.log line numbers and file name. Example jsFiddle.

// Avoid global functions via a self calling anonymous one (uses jQuery)
(function(MYAPP, $, undefined) {
    // Prevent errors in browsers without console.log
    if (!window.console) window.console = {};
    if (!window.console.log) window.console.log = function(){};

    //Private var
    var console_log = console.log;  

    //Public methods
    MYAPP.enableLog = function enableLogger() { console.log = console_log; };   
    MYAPP.disableLog = function disableLogger() { console.log = function() {}; };

}(window.MYAPP = window.MYAPP || {}, jQuery));


// Example Usage:
$(function() {    
    MYAPP.disableLog();    
    console.log('this should not show');

    MYAPP.enableLog();
    console.log('This will show');
});

Answer 5

This should override all methods of window.console. You can put it on the very top of your scripts section, and if you are on a PHP framework you can only print this code when your app environment is production, or if some kind of debug flag is disabled. Then you would have all your logs in your code working on development environments or in debug mode.

window.console = (function(originalConsole){
    var api = {};
    var props = Object.keys(originalConsole);
    for (var i=0; i<props.length; i++) {
        api[props[i]] = function(){};
    }
    return api;
})(window.console);

Answer 6

Warning: Shameless plug!

You could also use something like my JsTrace object to have modular tracing with module-level "switching" capability to only turn on what you want to see at the time.

http://jstrace.codeplex.com

(Also has a NuGet package, for those who care)

All levels default to "error", though you can shut them "off". Though, I can't think of why you would NOT want to see errors

You can change them like this:

Trace.traceLevel('ModuleName1', Trace.Levels.log);
Trace.traceLevel('ModuleName2', Trace.Levels.info);

Fore more docs, check out the Documentation

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