テーマ選択から重複要素を排除するように (#8385)

packages/client/src/scripts/array.ts

@@ -52,6 +52,17 @@ export function unique<T>(xs: T[]): T[] {
 	return [...new Set(xs)];
 }
 
+export function uniqueBy<TValue, TKey>(values: TValue[], keySelector: (value: TValue) => TKey): TValue[] {
+	const map = new Map<TKey, TValue>();
+
+	for (const value of values) {
+		const key = keySelector(value);
+		if (!map.has(key)) map.set(key, value);
+	}
+
+	return [...map.values()];
+}
+
 export function sum(xs: number[]): number {
 	return xs.reduce((a, b) => a + b, 0);
 }