JavaScript remove duplicates from an array
JavaScript Dasun Kalupahana 113 views
const nums = [1, 2, 2, 3, 3, 3];
const unique = [...new Set(nums)];
console.log(unique); // [1, 2, 3]
// Objects: keep the last item per id
const users = [{ id: 1, n: 'a' }, { id: 1, n: 'b' }, { id: 2, n: 'c' }];
const uniqueUsers = [...new Map(users.map((u) => [u.id, u])).values()];
console.log(uniqueUsers); // [{ id: 1, n: 'b' }, { id: 2, n: 'c' }]A Set keeps only unique values, so spreading it back into an array removes duplicates. For objects, dedupe by a key with a Map.
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