From d19031bc746d1b2552d740b894995de1bdfb71b3 Mon Sep 17 00:00:00 2001
From: Paul Miller <paul@paulmillr.com>
Date: Sun, 10 Dec 2023 22:23:26 +0000
Subject: [PATCH] utils: fix-up isBytes

---
 src/_assert.ts | 10 +++++++++-
 src/utils.ts   | 10 +++++++---
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/_assert.ts b/src/_assert.ts
index cd802fd..d9340f8 100644
--- a/src/_assert.ts
+++ b/src/_assert.ts
@@ -6,8 +6,16 @@ function bool(b: boolean) {
   if (typeof b !== 'boolean') throw new Error(`Expected boolean, not ${b}`);
 }
 
+function isBytes(a: unknown): a is Uint8Array {
+  return (
+    a != null &&
+    typeof a === 'object' &&
+    (a instanceof Uint8Array || a.constructor.name === 'Uint8Array')
+  );
+}
+
 function bytes(b: Uint8Array | undefined, ...lengths: number[]) {
-  if (!(b instanceof Uint8Array)) throw new Error('Expected Uint8Array');
+  if (!isBytes(b)) throw new Error('Expected Uint8Array');
   if (lengths.length > 0 && !lengths.includes(b.length))
     throw new Error(`Expected Uint8Array of length ${lengths}, not of length=${b.length}`);
 }
diff --git a/src/utils.ts b/src/utils.ts
index 82f5b5e..692a24e 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -11,8 +11,12 @@ export const u16 = (arr: TypedArray) =>
 export const u32 = (arr: TypedArray) =>
   new Uint32Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 4));
 
-function isBytes(a: any): a is Uint8Array {
-  return a instanceof Uint8Array || a.constructor.name === 'Uint8Array';
+function isBytes(a: unknown): a is Uint8Array {
+  return (
+    a != null &&
+    typeof a === 'object' &&
+    (a instanceof Uint8Array || a.constructor.name === 'Uint8Array')
+  );
 }
 
 // Cast array to view
@@ -169,7 +173,7 @@ export function checkOpts<T1 extends EmptyObj, T2 extends EmptyObj>(
 }
 
 export function ensureBytes(b: any, len?: number) {
-  if (!(b instanceof Uint8Array)) throw new Error('Uint8Array expected');
+  if (!isBytes(b)) throw new Error('Uint8Array expected');
   if (typeof len === 'number')
     if (b.length !== len) throw new Error(`Uint8Array length ${len} expected`);
 }