Remove duplicate objects from an array with Keys-CodePudding

How to filter array of objects by property? for example in this array if two or more objects have same properties like name and lastname I want to remove either of them and leave only unique one in an array. example arr:

    [ {name: "George", lastname: "GeorgeLast", age: 12},
      {name: "George", lastname: "GeorgeLast", age: 13},
      {name: "Bob", lastname: "GeorgeLast", age: 12}]

result should be either

 [ {name: "George", lastname: "GeorgeLast", age: 13},
   {name: "Bob", lastname: "GeorgeLast", age: 12}]

 [ {name: "George", lastname: "GeorgeLast", age: 12},
   {name: "Bob", lastname: "GeorgeLast", age: 12}]

CodePudding user response：

Apply the technique shown in this answer, which is:

function onlyUnique(value, index, self) {
  return self.indexOf(value) === index;
}

...but using findIndex with some criteria rather than just indexOf.

let people = [
  { name: "George", lastname: "GeorgeLast", age: 12 },
  { name: "George", lastname: "GeorgeLast", age: 13 },
  { name: "Bob", lastname: "GeorgeLast", age: 12 }
]

let result = people.filter(
  (person, index) => index === people.findIndex(
    other => person.name === other.name
      && person.lastname === other.lastname
  ));
console.log(result);

As for whether it keeps 12-year-old George or 13-year-old George, it is a matter of how findIndex works, which so happens to return the first matching element. So in your example case it will keep 12-year-old George.

CodePudding user response：

Another solution.
Here you don't need to iterate through the list n*n/2 times (if I count correctly).
On the other hand, this one looks less concise and uses more memory.
Use whichever you prefer.

const arr = [
  {name: "George", lastname: "GeorgeLast", age: 12},
  {name: "George", lastname: "GeorgeLast", age: 13},
  {name: "Bob", lastname: "GeorgeLast", age: 12}
];

const obj = {}
arr.forEach(v => {
  if (!obj[v.name]) {
    obj[v.name] = {}
  }
  if (!obj[v.name][v.lastname]) {
    obj[v.name][v.lastname] = v;
  }
})

const result = [];
Object.values(obj).forEach(nameObj =>
  Object.values(nameObj).forEach(surnObj => result.push(surnObj))
);

console.log(result)