如何删除对象数组中的重复项？

Question

I am trying to remove duplicates in Array of objects by using filter method in Javascript. This is what I tried

const students = [
    {
        name: 'Mark',
        age: 21
    },
    {
        name: 'Williams',
        age: 27
    },
    {
        name: 'Mark',
        age: 21
    }
]

const newStudents = students.filter(function(currentValue,index,arr) {
    return students.indexOf(currentValue) === index
})

console.log(newStudents)

Answer 1

I assume that you are trying to filter with one of the fields in the object. Then, you can filter like:

students.filter(obj => obj.name === 'Mark')

or you can define a filter function like:

function filterStudentByAge(student) {
  if(student.age > 21) return true
  else false
}

students.filter(filterStudent)

Answer 2

Your question is not that much clear to what you want to filter

but let assume that for example you want filter the stunted who's age is less then 25

So simply you can do like below:

const newStudents = students.filter(function(s,index,arr) {
    return s.age>25;
})

console.log(newStudents)