remove object from array if property value match

Question

I have array of objects that look like:

{
  "brandid": id,
  "brand": string,
  "id": id,
  "categoryId": id,
  "category": string,
  "factory": string,
  "series": string,
  "status": 0,
  "subStatus": 1
}

if the series property value matches another series property value in the other objects in the array, that object needs to be removed from the array.

Currently I have attempted to push them to a duplicate Array with :

      const seriesResCopy = seriesRes;
      const dupArray = []
      for (const thing of seriesResCopy) {
        for (const item of seriesRes) {
          if (thing.series === item.series) {
            dupArray.push(item);
          }
        }
      }

but this does not work. From examples I have seem my issue has been that I do not have a definite list of duplicate values to look for.

Any help would be much appreciated.

Answer 1

You could use a Set of series to filter out duplicates:

const exists = new Set();
seriesRes = seriesRes.filter(({series}) => !exists.has(series) && exists.add(series));

This uses: Array.prototype.filter , Object destructuring and some logical tricks.

The same can be done by mutating the array:

const exists = new Set();
for(const [index, {series}] of seriesRes.entries()) {
  if(!exists.has(series) {
    exists.add(series);
  } else {
    seriesRes.splice(index, 1);
  }
}

Answer 2

To filter duplicates from the array and keep the first instance:

let seriesWithoutDuplicates = seriesRes.filter((s, i, self) => {
    return self.findIndex(z => z.series === s.series) === i;
});