fix(node/zlib): cast Dataview and Buffer to uint8 (#21746)

This fixes point 2 of #20516 

This adds a conversion from Dataview/Buffer by returning `obj.buffer`
which can be converted to a `UInt8Array`.

Question: Regarding point 4 of the mentioned issue would it be
appropriate to copy the toU8 helper to the `zlib.mjs` methods?

1 files changed, 4 insertions, 0 deletions

diff --git a/ext/node/polyfills/_brotli.js b/ext/node/polyfills/_brotli.js
index bf099759b..cd54eedda 100644
--- a/ext/node/polyfills/_brotli.js
+++ b/ext/node/polyfills/_brotli.js
@@ -19,6 +19,10 @@ const toU8 = (input) => {
     return enc.encode(input);
   }
 
+  if (input.buffer) {
+    return new Uint8Array(input.buffer);
+  }
+
   return input;
 };