uniqueBy
Returns all unique values of an array, based on a provided comparator function.
Use Array.prototype.reduce()
and Array.prototype.some()
for an array containing only the first unique occurrence of each value, based on the comparator function, fn
.
The comparator function takes two arguments: the values of the two elements being compared.
typescript
const uniqueBy = (arr: any[], fn: Predicate) =>
arr.reduce((acc, v) => {
if (!acc.some((x: any) => fn(v, x))) acc.push(v);
return acc;
}, []);
typescript
uniqueBy(
[
{ id: 0, value: "a" },
{ id: 1, value: "b" },
{ id: 2, value: "c" },
{ id: 1, value: "d" },
{ id: 0, value: "e" },
],
(a: any, b: any) => a.id == b.id
); // [ { id: 0, value: 'a' }, { id: 1, value: 'b' }, { id: 2, value: 'c' } ]