Best way to find smallest value from array containing objects

Question

I wants to find out the object which holds the smallest value of a key in an array.

var tempArr = [{name: 'john', age: 23}, {name: 'jonny', age: 27}, {name: 'roony', age: 13}, {name: 'david', age: 33}];

I want the result to be

{name: 'roony', age: 13}

without using for loop is there any direct way to find out the result, like we can do for plain array

for example: if array is -

var arr = [11,4,22,3,5,55];

we can achieve the same by:

Math.min.apply(null, arr)

@epascarello: sorry typo mistake, they are numbers. do sort method works with the array containing objects ? — robieee, Jan 15 '15 at 18:16
Here's the detail you need to make it work @robieee http://stackoverflow.com/questions/1129216/sorting-objects-in-an-array-by-a-field-value-in-javascript — Mic, Jan 15 '15 at 18:17
@DanielRobinson: There are many good reasons to avoid `for`-loops. Chief among then is the fact that they do little to express programmer intent, focusing instead on mostly irrelevant bookkeeping instructions to the computer. This video explains fairly well: http://vimeo.com/43382919 — Scott Sauyet, Jan 15 '15 at 18:58
In many cases, I would agree. But for this example, compare how it would be done with a `for` loop to my answer below that uses `reduce`. Is the latter really that much less concerned with irrelevant bookkeeping? — Daniel Robinson, Jan 15 '15 at 19:03

Daniel Robinson · Answer 1 · 2015-01-15T18:47:18.813

7

You should use reduce:

min = tempArr.reduce(function(previousValue, currentValue, index, array) {
    return (currentValue.age < previousValue.age ? currentValue : previousValue);
});

Any solution involving sort will be suboptimal.

edited Jan 15 '15 at 18:47

answered Jan 15 '15 at 18:27

Daniel Robinson

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Keep forgetting about reduce. +1 – epascarello Jan 15 '15 at 18:30
@Daniel Robinson: Why would sort be sub-optimal? – Max Heiber Jan 15 '15 at 19:55
1

Finding the minimum only requires n comparisons. Sorting requires more than that. (Quicksort, for example, requires n log n comparisons in the average case, and n^2 comparisons in the worst case). – Daniel Robinson Jan 15 '15 at 20:07

Max Heiber · Accepted Answer · 2023-03-05T13:34:33.970

3

@antyrat's solution is more explicit, but I figured I'd provide another way:

var people=[{name: 'john', age: 23}, {name: 'jonny', age: 27}, {name: 'roony', age: 13}, {name: 'david', age: 33}];

var youngestPerson = people.reduce(function(youngestPerson, person){
    return person.age < youngestPerson.age ? person : youngestPerson; 
}, people[0]);

console.log(youngestPerson);

edited Mar 05 '23 at 13:34

answered Jan 15 '15 at 18:29

Max Heiber

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score 0 · Answer 3 · answered Jan 15 '15 at 18:18

Yes, you can use sort method:

var tempArr = [{name: 'john', age: '23'}, {name: 'jonny', age: '27'}, {name: 'roony', age: '13'}, {name: 'david', age: '33'}];
tempArr = tempArr.sort( function( a, b ) {
    var AgeA = parseInt( a.age, 10 );
    var AgeB = parseInt( b.age, 10 )
    if ( AgeA < AgeB ) return -1;
    else if ( AgeA > AgeB ) return 1;
    else return 0;
});
console.log(tempArr);
console.log(tempArr[0]); // is the record with smallest `age` value

Sorting is a very inefficient way to find a minimum value, and a for loop would be less code. — Daniel Robinson, Jan 15 '15 at 18:20

Best way to find smallest value from array containing objects

3 Answers3