Get key with minimum value

Question

I have an array like this: arr = {lst1: 300, lst2: 381, lst3: 4, lst4: 4, lst5: 49, …}

And I'm trying get the lowest value with key using Javascript.

What I've tried:

alert(Math.min.apply(Math, arr)); returns Infinity I don't know why

I got this on Google, just for try:

var keys = Object.keys(arr).map(Number).filter(function(a){
    return arr[a];
}); alert(Math.min.apply(Math, keys));

returns Infinity too

I want something more complete, like this output: "The lowest value is 2 from lst9".

I really tried fix it myself before asking here, but without success! Can you help me fix this "Infinity" issue? Thank you.

Answer 1

You can get the key and value using Object.entries:

var arr = {
  lst1: 300,
  lst2: 381,
  lst3: 4,
  lst4: 4,
  lst5: 49
};

function lowestValueAndKey(obj) {
  var [lowestItems] = Object.entries(obj).sort(([ ,v1], [ ,v2]) => v1 - v2);
  return `Lowest value is ${lowestItems[1]}, with a key of ${lowestItems[0]}`;
}

var lowest = lowestValueAndKey(arr);
console.log(lowest);