How to sort an array of integers correctly

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Trying to get the highest and lowest value from an array that I know will contain only integers seems to be harder than I thought.

var numArray = [140000, 104, 99];
numArray = numArray.sort();

I’d expect this to show 99, 104, 140000. Instead it shows 104, 140000, 99. So it seems the sort is handling the values as strings.

Is there a way to get the sort function to actually sort on integer value?

First answer

By default, the sort method sorts elements alphabetically. To sort numerically just add a new method which handles numeric sorts (sortNumber, shown below) –

function sortNumber(a, b) {
  return a - b;

var numArray = [140000, 104, 99];


In ES6, you can simplify this with arrow functions:

numArray.sort((a, b) => a - b); // For ascending sort
numArray.sort((a, b) => b - a); // For descending sort

Second answer

array.sort does a lexicographic sort by default, for a numeric sort, provide your own function. Here’s a simple example:

function compareNumbers(a, b)
    return a - b;


Also note that sort works “in place”, there’s no need for the assignment.

Third answer

This answer is equivalent to some of the existing answers, but ECMAScript 6 arrow functions provide a much more compact syntax that allows us to define an inline sort function without sacrificing readability:

numArray = numArray.sort((a, b) => a - b);

It is supported in most browsers today.

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