无法仅过滤数组的唯一值

Question

I'm trying to write a function that accepts an array of objects, selects only a specific key in the objects and returns only the unique values of that array into a new "filtered" array. I'm trying to use Array.filter and keep getting errors that my filtered array is undefined. Where have I gone wrong?

const findUniques = function(arr) {


let rawArray = arr.map(res => res.id);

let filtered = rawArray.filter((id) => {
    return filtered.indexOf(id) === -1;
});
console.log(filtered)


};

Here is a mock of the array I'm filtered over.

1630489261, 1630489261, 1630489261, 1630489313, 1630489313, 1630489261, 1630489313, 1707502836, 1590711681, 1588295455, 1630489313, 1707502836, 1588295455, 1707502836, 1590711681, 1707502836, 1707502836, 1707502836, 1707502836, 1707502836, 1588295455, 1588295455

If I set filtered as a global variable it gets filled but it is not being filtered. IE filtered is being filled with everything in the rawArray.

Answer 1

Using Array#filter

 rawArray = [1, 2, 3, 2, 3, 1, 4]; filtered = rawArray.filter((e, i) => rawArray.indexOf(e) === i); console.log(filtered); 

Using Array#reduce

 let rawArray = [1, 2, 3, 2, 3, 1, 4], filtered = rawArray.reduce(function (acc, item) { if (!acc.includes(item)){ acc.push(item); } return acc; }, []); console.log(filtered); 

Answer 2

const values = [1630489261, 1630489261, 1630489261, 1630489313, 1630489313, 1630489261, 1630489313, 1707502836, 1590711681, 1588295455, 1630489313, 1707502836, 1588295455, 1707502836, 1590711681, 1707502836, 1707502836, 1707502836, 1707502836, 1707502836, 1588295455, 1588295455];


function unique(array) {
  return array.reduce((a,b) => {
    let isIn = a.find(element => {
        return element === b;
    });
    if(!isIn){
      a.push(b);
    }
    return a;
  },[]);
}

let ret = unique(values);

console.log(ret);

https://jsfiddle.net/26bwknzf/4/