JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://getfirebug.com/firebug-lite-debug.js"></script>

JavaScript

var data = [
    [1, "07/28/2014"],
    [2, "07/29/2014"],
    [3, "07/28/2014"],
    [4, "07/30/2014"],
    [5, "07/28/2014"],
];
var data2 = [
    [1, "07/28/2014"],
    [2, "07/29/2014"],
    [3, "07/29/2014"],
    [4, "07/29/2014"],
    [5, "07/29/2014"],
];

    function removeDuplicates(Array){    
        this._newArray = [];
        this.numberOfDuplicates = 0;
        this.listDuplicates = [];
        //Remove Duplicates    
            for(i=0;i<Array.length;i++){      
                for(j=0;j<Array.length;j++){
                    if(!Array[i][1]) //skip the current loop if index is empty
                        break;
                    if(Array[i][1]==Array[j][1] && i!=j){
                        this.listDuplicates.push(Array[j]);                            
                        Array[j]=0;
                        this.numberOfDuplicates+=1; //increase counter for dupes
                    }
                }    
            }
        //Recreate Array

        this.newArray = function(){
            for(i=0;i<Array.length;i++){
                if(Array[i])
                    this._newArray.push(Array[i]);
            }
        return this._newArray;
        }
}

var data = new removeDuplicates(data);
console.log(data.newArray());
console.log(data.numberOfDuplicates + " Duplicates");
console.log(data.listDuplicates);

console.log("\n");
var data2 = new removeDuplicates(data2);
console.log(data2.newArray());
console.log(data2.numberOfDuplicates + " Duplicates");
console.log(data2.listDuplicates);