Add a merge function

web/packages/utils/array.ts

@@ -28,3 +28,21 @@ export const firstNonEmpty = (ss: (string | undefined)[]) => {
     for (const s of ss) if (s && s.length > 0) return s;
     return undefined;
 };
+
+/**
+ * Merge the given array of {@link Uint8Array}s in order into a single
+ * {@link Uint8Array}.
+ *
+ * @param as An array of {@link Uint8Array}.
+ */
+export const mergeUint8Arrays = (as: Uint8Array[]) => {
+    // A longer but better performing replacement of
+    //
+    //     new Uint8Array(as.reduce((acc, x) => acc.concat(...x), []))
+    //
+
+    const len = as.reduce((len, xs) => len + xs.length, 0);
+    const result = new Uint8Array(len);
+    as.reduce((n, xs) => (result.set(xs, n), n + xs.length), 0);
+    return result;
+};