Remove duplicates from an array?

Question

var arr = [1,2,3,4,3,5];
how could I remove duplicates on any given array?

Answer 1

var arr = [1, 2, 3, 4, 3, 5];
var new_arr = [];
for (var i = 0; i < arr.length; i++) {
var flag = 0;
for (var j = 0; j < new_arr.length; j++) {
if (arr[i] === new_arr[j])
flag = 1;
}
if (flag === 0)
new_arr.push(arr[i]);
}
alert(new_arr);

Answer 2

var arr = [1,2,3,4,3,5];
Array.prototype.uni = function(){
return this.filter((v,i,a)=>a.indexOf(v,i+1)===-1?true:false);
}
alert(arr.uni());
https://code.sololearn.com/WBA29niGTZsj/?ref=app

Answer 3

Loop thru the list adding each number to another new list but first checking if that number is in the new list. If the number is already in the new list you have a duplicate. Then just remove it.