How to return multiple values from an array object as new variables?

Question

My array looks like this:

var points = [{category: "Category A", correct: "0"},{category: "Category B", correct: "4"}];

I am trying to see which category has the highest number of correct. I started by using Math.max on my array map to determine which one is the highest value (which it returns 4.) But when I try to expand on that return it begins defaulting to NaN.

var res = Math.max.apply(Math,points.map(function(k){
    return k.correct;
}));

o.correct in this instance will return 4.

JSFiddle

What I've tried:

Switching my return to k.category

-> This returns "NaN"
Treating it as a function and storing both variables in the Math.max, this will pull both values of the object, but it does it for both objects in the array.

Math.max.apply(Math,points.map(function(k){ var highestCat = k.category; var highestCor = k.correct; alert(highestCat + highestCor); }));

Any ideas on what I could do to be able to store these as 2 separate variables I could reference later on?

score 1 · Accepted Answer · 2018-08-02 14:07:20Z

1

You can sort the array and grab the first element

var points = [{category: "Category A", correct: "0"},{category: "Category B", correct: "4"}];
var sorted = points.sort((a,b)=>b.correct - a.correct)
var highest = sorted[0];
alert(highest.category + highest.correct);

same thing with object destructuring

var points = [{category: "Category A", correct: "0"},{category: "Category B", correct: "4"}];   
var {category:highestCateogry,correct:highestCorrect} = points.sort((a,b)=>b.correct - a.correct)[0];
alert(highestCateogry + highestCorrect);

edited Aug 2, 2018 at 14:07

answered Aug 2, 2018 at 13:58

user2033671

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3 Comments

ghostmice Over a year ago

I didn't think about sorting, but after trying to plug this in, it seems to only return [object Object]. Check this fiddle. Edit: just saw your edit to the answer.

user2033671 Over a year ago

When you alert a object it implicitly calls the objects toString method. sorted is an array, the default toString on most objects is [object Object], highest is the first element in the sorted array {category:"Category B", correct: "4"} again uses the default toString of [object Object] since it does not define it's own toString function

Vladu Ionut Over a year ago

Using reduce(or any other loops) is faster than sorting

Vladu Ionut · Accepted Answer · 2018-08-02 14:20:06Z

1

You can use Array reduce

let points = [{category: "Category A", correct: "0"},{category: "Category B", correct: "4"},{category: "Category C", correct: "1"},{category: "Category D", correct: "5"},{category: "Category E", correct: "0"}];


const max = points.reduce((currentMax,newMax) => { 
return +currentMax.correct  < +newMax.correct ?  newMax :currentMax
})

console.log(max)

edited Aug 2, 2018 at 14:20

answered Aug 2, 2018 at 14:10

Vladu Ionut

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Comments

Michael · Accepted Answer · 2018-08-02 13:54:51Z

0

You have NaN because correct is a string and not a number. Use parseInt function to convert the string into integer

answered Aug 2, 2018 at 13:54

Michael

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1 Comment

ghostmice Over a year ago

I'd like to keep it a string so I can compare the value in conditionals later on. ie: if highestCat = category a

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