4 ways to remove duplicates from an array

removeDuplicates.js

let a = [1,2,5,1,1,2,8];

// 1. Using for loop
let b = [];
let len = a.length;
for(let i=0; i<len; i++) {
  if(b.indexOf(a[i]) === -1) {
    b.push(a[i]);
  }
}
console.log(b);

// 2. Using sort and remove
let c = [];
let _temp;
let len1 = a.length;
a.sort()
for(let i=0; i<len1; i++) {
  if(_temp !== a[i]) {
    c.push(a[i]);
    _temp = a[i];
  }
}
console.log(c);

// 3. using hash table (object)

let arr = [1,2,5,1,1,2,8];
let obj = {}

for (val of arr) {
  obj[val] = parseInt(val);
}

console.log(Object.values(obj))

// 4. using hash table (ES6 set) - one line
console.log([... new Set(arr)])