Sort a Javascript Array by frequency and then filter repeats

Question

What is an elegant way to take a javascript array, order by the frequency of the values, and then filter for uniques?

So,

[\"apples\", \"oranges\", \"o

Answer 1

Let me put a minimal code to get unique values (and with frequencies) in ES6.

var arr = ["apples", "oranges", "oranges", "oranges", "bananas", "bananas", "oranges"];
console.log([...new Set(arr)])

It is also applied to array of objects to aggregate some properties.

var arr = [{"fruit":"apples"}, {"fruit":"oranges"}, {"fruit":"oranges"}, {"fruit":"oranges"}, {"fruit":"bananas"}, {"fruit":"bananas"}, {"fruit":"oranges"}];
console.log(arr.reduce((x,y)=>{if(x[y.fruit]) {x[y.fruit]++;return x;} else {var z={};z[y.fruit]=1;return Object.assign(x,z);}},{}))

Answer 2

// returns most frequent to least frequent

Array.prototype.byCount= function(){
    var itm, a= [], L= this.length, o= {};
    for(var i= 0; i<L; i++){
        itm= this[i];
        if(!itm) continue;
        if(o[itm]== undefined) o[itm]= 1;
        else ++o[itm];
    }
    for(var p in o) a[a.length]= p;
    return a.sort(function(a, b){
        return o[b]-o[a];
    });
}

//test

var A= ["apples","oranges","oranges","oranges","bananas","bananas","oranges"];
A.byCount()

/* returned value: (Array) oranges,bananas,apples */