Return highest value or equal values javascript

Question

I'm creating a voting system and I have the following object:

var obj1 = { Mcds: 2, Pret: 2, kfc: 2, BK: 1 }

or (depending on the votes) it could be:

var obj2 = { Mcds: 2, Pret: 2, BK: 3 }

What I want is to display the most voted restaurant or restaurants.

I can achieve this with the obj2 example using the following code:

var obj2Keys = Object.keys(obj2);

var mostVoted = obj2Keys.reduce(function(previousValue, currentValue){
    return obj2[previousValue] > obj2[currentValue] ? previousValue : currentValue;
}); // returns 'BK'

When I use the above code on the obj1 example I get 'kfc' what I want is 'kfc' 'Pret' 'Mcds' (in no particular order).

Barmar · Accepted Answer · 2016-02-09 16:46:21Z

1

You need to accumulate all the winning names into an array. When you get a tie for the high vote, you add the element to the array; when you get a higher vote, you start a new array.

var obj1 = {
  Mcds: 2,
  Pret: 2,
  kfc: 2,
  BK: 1
}

var high_vote = 0;
var winners;
for (var key in obj1) {
  if (obj1.hasOwnProperty(key)) {
    if (obj1[key] > high_vote) {
      winners = [key];
      high_vote = obj1[key];
    } else if (obj1[key] == high_vote) {
      winners.push(key);
    }
  }
}

alert(winners);

edited Feb 9, 2016 at 16:46

answered Feb 9, 2016 at 16:21

Barmar

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2 Comments

우두머리 Over a year ago

"most voted restaurant or restaurants", so if you have {Mcds: 2, Pret: 3, BK: 3} you espect to have 2 winners. your code is returning the last winner found.

Barmar Over a year ago

I forgot to update high_vote in the if. Now it works.

trincot · Accepted Answer · 2016-02-09 16:27:25Z

0

Add this below your existing code:

var mostVotedArray = obj2Keys.filter(function(currentValue){
    return obj2[currentValue] == obj2[mostVoted];
});

The new variable will list the "winners" as an array.

edited Feb 9, 2016 at 16:27

answered Feb 9, 2016 at 16:19

trincot

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3 Comments

Barmar Over a year ago

You need to do a first pass to set mostVoted.

trincot Over a year ago

That's what I said "add this below your existing code"

Barmar Over a year ago

In his code, mostVoted is a key, not a value. So it should be == obj2[mostVoted].

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