How to compare two arrays of objects and delete the duplicates in javascript

Question

(This question already has answers here): question from:https://stackoverflow.com/questions/66052884/how-to-compare-two-arrays-of-objects-and-delete-the-duplicates-in-javascript

Answer 1

You can use a Set for all your identifiers and use it to filter out ids that show up on the other array.

function filterById(mainArr, filterArr){
     let idSet = new Set(filterArr.map(obj => obj.id));
     return mainArr.filter(obj => !idSet.has(obj.id));
}

This will remove all objects in mainArr with a specific id that show up in filterArr.

Example here:

let arr = [{
    "first_name": "Wanda",
    "id": 27,
    "last_name": "Walhai"
  },

  {
    "first_name": "Victoria",
    "id": 26,
    "last_name": "Viperfisch"
  }
]

let filterArr = [{
  "first_name": "Victoria",
  "id": 26,
  "last_name": "Viperfisch"
}]

function filterById(mainArr, filterArr){
     let idSet = new Set(filterArr.map(obj => obj.id));
     return mainArr.filter(obj => !idSet.has(obj.id));
}

console.log(filterById(arr, filterArr));