Filtering duplicates from an array of objects

Question

I have an array that needs to be populated without duplicate objects. However, I am constantly being sent back an array with the duplicate values. Can anyone tell me what I'm doing wrong here and how to fix it?

let holderArr = [
{
    one: "A",
    two: 2,
    three: "String"
},
{
    one: "B",
    two: 2,
    three: "String"
},
{
    one: "A",
    two: 2,
    three: "String"
}]

function removeDuplicates(array){
    let filteredArr = [];
    return duplicateArray.filter((duplicate) => {
        let id = [duplicate.one, duplicate.two].join("|");
        if(filteredArr.indexOf(id) === -1){
            filteredArr.push(id);
        }
        return out;
    })
}
removeDuplicates(holderArr);

also, I would read up on filter https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter — Robbie Milejczak, Nov 09 '17 at 19:34
@dupeflaggers even if theres already a *filtering an array* answer out there, it looks like the OP is already aware of that and on the way, we just need to do a bit fine tuning on his code. — Jonas Wilms, Nov 09 '17 at 19:36

score 0 · Answer 1 · answered Nov 09 '17 at 19:43

am not a professional, but this way it would work.

let holderArr = [1,3,5];

function removeDuplicates(array){
    var filteredArr = [];
for(let i=0; i<array.length; i++){
  if(filteredArr.indexOf(array[i]) === -1){
            filteredArr.push(array[i]);
        }
    }
    return filteredArr;
}
removeDuplicates(holderArr);

I took a look on your code. you have mistaken in somethings. it will work after these edits, try to figure out where did u get it wrong.

function removeDuplicates(array){
  let filteredArr = [];
  return array.filter((id) => {
      if(filteredArr.indexOf(array[id]) === -1){
          filteredArr.push(array[id]);
      }
      return filteredArr;
  })
}
removeDuplicates(holderArr);

Phillip Thomas · Answer 2 · 2017-11-09T19:40:09.240

-1

Looks like you are referring to an unknown variable duplicateArray, try:

function removeDuplicates(array){
  return array.filter(function(item, pos, self) {
    return self.indexOf(item) == pos;
  })
}

let uniqueArray = removeDuplicates(holderArr);

This will populate uniqueArray with what you want.

edited Nov 09 '17 at 19:40

answered Nov 09 '17 at 19:33

Phillip Thomas

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Filtering duplicates from an array of objects

2 Answers2