fronterior · April 13, 2021 09:57
diff --git a/group-by.ts b/group-by.ts
 const groupBy = <T, K extends keyof any>(f: (p: T) => K, arr: T[]) => arr.reduce((acc, val) => {
  const key = f(val);
  acc[key]?.push(val) ?? (acc[key] = [val]);
  return acc;
 }, {} as Record<K, T[]>);
	const groupBy = <T, K extends keyof any>(f: (p: T) => K, arr: T[]) => arr.reduce((acc, val) => {
	const key = f(val);
	acc[key]?.push(val) ?? (acc[key] = [val]);
	return acc;
	}, {} as Record<K, T[]>);