gistfile1.txt

var obj = {};
var arr = [];
 
for(var i=0; i < 1280000; i++) { 
  obj[i] = "a"; 
	arr.push("a");
}

var start = process.hrtime(); 

for(var x in obj) { 
	if(obj.hasOwnProperty(x)) {
	
	}
}; 

console.log("obj - for: " + process.hrtime(start)[1] / 1e6);

var start = process.hrtime(); 

Object.keys(obj).forEach(function(v) {
	
}); 

console.log("obj - forEach: " + process.hrtime(start)[1] / 1e6);

var start = process.hrtime(); 

for(var y = 0; y < arr.length; y++ ) { 
	
}; 

console.log("arr - for: " + process.hrtime(start)[1] / 1e6);

var start = process.hrtime(); 

arr.forEach(function(v) {

});

console.log("arr - forEach: " + process.hrtime(start)[1] / 1e6);

//Output
obj - for: 564.066452
obj - forEach: 499.227533
arr - for: 5.746904
arr - forEach: 68.975154