Array changed into Object During the exection

function delalert(select_rule_id) {
  console.log("***** Entering delalert *****");

  const arr = select_rule_id;

  console.log(arr);
  console.log(typeof arr);

  console.log("Selected Rule id" + typeof select_rule_id);
  console.log("Selected Rule id" + select_rule_id);

  select_rule_id2 = Object.entries(select_rule_id)

  console.log("Selected Rule id" + typeof select_rule_id2);
  console.log("Selected Rule id" + select_rule_id2);

  var derivationName_col = "";
  var maincollection = GetTableUICollectn();
  var selectrule_col = select_rule_id2.split(',');

  for (var key in maincollection) {
    /*for (var val in select_rule_id)*/
    if (selectrule_col.includes(key)) {
      var derivation_id = maincollection[key];
      var derivationName = maincollection[key].Derivation_Name;
      derivationName_col = derivationName_col + "<br/>" + derivationName;
    }
  }
  console.log("NameCollection" + derivationName_col);
  document.getElementById('Checked_Rule').innerHTML = derivationName_col.toString();

  /*return derivationName_col;*/
  
  console.log("***** Exiting delalert *****");
}

This is my code here select_rule_id passing as array.after that print that array it shows array.(console.log(arr);) but i print that array type it show object (console.log(typeof arr);)

I also assign that array to new variabe.till shows that array as object .I print that object also but it not shown key value type.

i attached screenshot of my browser console.

>Solution :

That is a Javascript’s behavior. We set the array but it’s actually an object. You can check if the variable is array or not using

var isArr = data instanceof Array;
var isArr = Array.isArray(data);

check this out Why does typeof array with objects return "object" and not "array"?