console-monkey-patch.js

// Avoid `console` errors in browsers that lack a console.
(function() {
    var method;
    var noop = function () {};
    var methods = [
      'assert', 'clear', 'count', 'debug', 'dir', 'dirxml', 'error',
      'exception', 'group', 'groupCollapsed', 'groupEnd', 'info', 'log',
      'markTimeline', 'profile', 'profileEnd', 'table', 'time', 'timeEnd',
      'timeStamp', 'trace', 'warn'
    ];
    var length = methods.length;
    var console = (window.console = window.console || {});
 
    while (length--) {
      method = methods[length];

      // Only stub undefined methods.
      if (!console[method]) {
        console[method] = noop;
      }
    }
}());

grunt-console-after.js

(function( etm, undefined ) {
  var myVariable = 0;
  
  
  
  etm.init = function() {
  
    myVariable += 1;
  };
  
  function secret() {
  
    myVariable += 2;
  };
}( window.etm = window.etm || {} ));

grunt-console-before.js

(function( etm, undefined ) {
  var myVariable = 0;
  
  console.log( "test 1" );
  
  etm.init = function() {
    console.log( "test 2" );
    myVariable += 1;
  };
  
  function secret() {
    console.log( "test 3" );
    myVariable += 2;
  };
}( window.etm = window.etm || {} ));

grunt-remove-logging.js

module.exports = function( grunt ) {

  grunt.initConfig({
    pkg: grunt.file.readJSON( "package.json" ),
    removelogging: {
      dist: {
        src: "src/<%= pkg.name %>.js",
        dest: "build/<%= pkg.name %>.clean.js",
        options: {}
      }
    }
  });

  grunt.loadNpmTasks( "grunt-remove-logging" );

  grunt.registerTask( "default", ["removelogging"] );

};

javascript-debug.js

debug.log( "test" );           // Level 1
debug.debug({ msg: "test" });  // Level 2
debug.info( false );           // Level 3
debug.warn( 42 );              // Level 4
debug.error( [1, 2, 3] );      // Level 5

uglify-command-line.sh

# Uglify
uglifyjs --define DEBUG=false "hello.js" > "hello.min.js"

# Uglify2
uglifyjs --compress --define DEBUG=false hello.js -o hello.min.js

uglify-source-code.js

if ( typeof DEBUG === "undefined" ) DEBUG = true; 

function sayHello() {
  DEBUG && console.log( "Hello World!" ); 
}