Question

I am trying to store values in array using JavaScript, but I get strange error:

let a = 1;
for (i = 0; i < 4; i++) {

  var all = new Array();
  all[i] = a;
  a++;
}

console.log(all[1]);
console.log(all[2]);
console.log(all[3]);

For all[1] and all[2] I am getting undefined error, but all[3] is working fine.

Answer 1

You are reassigning your array in every loop iteration (which deletes everything in it) instead of only before the whole loop.

This should work as expected:

var a = 1;
var all = new Array();
for(i=0;i<4;i++)
{
    all[i]=a;
    a++;
}

alert(all[1]);
alert(all[2]);
alert(all[3]);