JSFiddle - React, Tailwind, and code Playground

HTML

<div id="result">Property without unique entries:</div>

JavaScript

Array.prototype.allValuesSame = function() {
    for(var i = 1; i < this.length; i++) {
        if(this[i] !== this[0])
            return false;
    }
    return true;
}

var data = [
   {Date: "2016-04-27T09:03:45Z", Name: "Tito", Title: "Developer", Department:"IT", Company: "XXX"},
   {Date: "2016-04-27T08:07:45Z", Name: "Tito", Title: "Developer", Department:"IT", Company: "XXX"},
   {Date: "2016-04-27T10:23:45Z", Name: "Tito", Title: "Developer", Department:"IT", Company: "XXX"}
]

var tmpPropValues = {};

for (var property in data[0]) {
	tmpPropValues[property] = [];
  
	for(var i = 0; i < data.length; i++) {
		var obj = data[i];
  
  	// store temporary in array
    if (obj.hasOwnProperty(property)) {
      var value = obj[property];
      
      tmpPropValues[property].push(value);
    }
  }
  
	if(tmpPropValues[property].allValuesSame()) {
	  delete tmpPropValues[property];
  }
}

for(var prop in tmpPropValues) {
	var tmp = document.getElementById("result").innerHTML;
  document.getElementById("result").innerHTML = tmp+" "+prop;

}