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antlis/group-by.js

Created April 16, 2026 20:13
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Groups array items by a computed key. Lightweight alternative to Lodash groupBy.
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group-by.js
export function groupBy(arr, keyFn) {
return arr.reduce((acc, item) => {
const key = keyFn(item);
(acc[key] ||= []).push(item);
return acc;
}, {});
}
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antlis commented Apr 16, 2026

Use case:

groupBy(users, u => u.role);

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