javascript - undefined elements inside an array which has randomized numbers inside it

Question

so I created this script to generate an array of 5 random numbers where the numbers must be unique, but I get +2 undefined elements. There are 5 numbers which are unique but the length of the array isn't anymore 5

let arr = [];
while (arr.length <= 5) {
  let x = Math.floor(Math.random() * 11);
  if (arr.includes(x) === false) {
    arr.push(x);
  }
  arr.length += 1;
}
console.log(arr);

question from:https://stackoverflow.com/questions/65927947/undefined-elements-inside-an-array-which-has-randomized-numbers-inside-it

Answer 1

You should remove the arr.length += 1 line. The array length will be automatically incremented each time a new element is pushed, no need to modify it by yourself: this is a bad practice.