ways to check for empty array in a conditional in JS [duplicate]

Question

I'm wondering why my conditional statement where I'm trying to sort out the edge case of the input array being empty doesn't seem to work. With my current test case, the result I get is NaN (no idea why). If I change the conditional to if (array.length === 0), then my code functions the way I want it to. Isn't [] the correct representation of an empty array though?

function getAvg(array) {
  if (array === []) {
    return 0;
  }
  var sum     = 0;
  var average = 0;
  var length  = array.length;
  for (var i  = 0; i < length; i++) {
      sum += array[i];
  }
  average = sum / length;
  return average
}

var input  = [];
var result = getAvg(input);

console.log('should be 0:', result);

TLDR; [] is a new different empty array, not the representation of any empty array. Think object references. — Ayush Gupta
– Ayush Gupta, Commented Aug 4, 2021 at 16:57
You are getting NaN because the array length is 0, which means (sum / length) is 0 / 0 which is NaN because you can't divide by zero. — nullromo
– nullromo, Commented Aug 4, 2021 at 17:05

Dibash Sapkota · Accepted Answer · 2021-08-04 16:59:11Z

0

You can check if length of array is greater than 0\

 if(arr.length>0){}

answered Aug 4, 2021 at 16:59

Dibash Sapkota

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