How to remove duplicates element from array

const array = ["a","b","c","d","a","c","e","f"];
const m1 = [...new Set(array)];
console.log(m1);
// ["a", "b", "c", "d", "e", "f"] 

const array = ["a","b","c","d","a","c","e","f"];
let obj = {};
for (let arr of array){
obj[arr]=true;
}
console.log(Object.keys(obj));
// ["a", "b", "c", "d", "e", "f"] 

const array = ["a","b","c","d","a","c","e","f"];
const m3 = [];
for(var i = 0;i<array.length;i++){
const arr = array[i];
m3.indexOf(arr) === -1 && m3.push(arr);
}
console.log(m3)
// ["a", "b", "c", "d", "e", "f"]

const array = ["a","b","c","d","a","c","e","f"];
const m4 = array.filter((el,index)=>array.indexOf(el) == index);
console.log(m4);
// ["a", "b", "c", "d", "e", "f"]