How to quickly and conveniently disable all consol

Question

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

Answer 1

I developed a library for this usecase: https://github.com/sunnykgupta/jsLogger

Features:

1. It safely overrides the console.log.
2. Takes care if the console is not available (oh yes, you need to factor that too.)
3. Stores all logs (even if they are suppressed) for later retrieval.
4. Handles major console functions like log, warn, error, info.

Is open for modifications and will be updated whenever new suggestions come up.

Answer 2

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 3

As far as I can tell from the documentation, Firebug doesn't supply any variable to toggle debug state. Instead, wrap console.log() in a wrapper that conditionally calls it, i.e.:

DEBUG = true; // set to false to disable debugging
function debug_log() {
    if ( DEBUG ) {
        console.log.apply(this, arguments);
    }
}

To not have to change all the existing calls, you can use this instead:

DEBUG = true; // set to false to disable debugging
old_console_log = console.log;
console.log = function() {
    if ( DEBUG ) {
        old_console_log.apply(this, arguments);
    }
}

Answer 4

I am surprised that of all those answers no one combines:

• No jquery
• Anonymous function to not pollute global namespace
• Handle case where window.console not defined
• Just modify the .log function of the console

I'd go for this:

(function () {

    var debug = false

    if (debug === false) {
        if ( typeof(window.console) === 'undefined') { window.console = {}; }
        window.console.log = function () {};
    }
})()

Answer 5

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');
});