Min and max index in JavaScript array

Question

I have simple question. I have JS array like that:

data[-5]=[...];
data[-2]=[...];
data[-1]=[...];
data[4]=[...];
data[6]=[...];
data[7]=[...];

How can I get automatically the minimum (data[-5]) and maximum (data[7]) element?

• Pointy: Negative indexes to arrays are improper in JavaScript. They'll work, sort-of, but if you do something like serialize the array with JSON.stringify you'll lose those, and they won't be reflected in the array length.
• Dean.DePue: Why would you ever have a negative index??
• Bergi: @Pointy: I haven't heard of any language whose arrays could be indexed with negative values...
• Pointy: @Bergi I think you could/can do it in Pascal :)
• LS_ᴅᴇᴠ: @Bergi VB also supports them.

Answer 1

Negative indexes are not actual indexes. They won't work all time. They are like just as any other property of an object.

However, you could do what you want by iterating through the enumerable properties(Which is bad for an array, but nevertheless) and adding number properties to an Array.

var idxs = Object.keys(arr).filter(isFinite); // just take the Number properties
var min = Math.min.apply(Math, idxs),
 max = Math.max.apply(Math, idxs);

Answer 2

Short with no loops:

var keys = Object.keys(data);
var sorted = keys.sort(function(a, b){return a-b});
var min = data[sorted[0]];
var max = data[sorted[sorted.length-1]];