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