From a7e57afd96ea538c32053b6c9537b7241e56e437 Mon Sep 17 00:00:00 2001
From: Yagiz Nizipli <yagiz@cloudflare.com>
Date: Tue, 3 Sep 2024 16:34:59 -0400
Subject: [PATCH] simplify zlib internals

---
 src/node/internal/internal_zlib.ts      | 75 +++----------------------
 src/node/internal/internal_zlib_base.ts |  4 +-
 src/node/internal/zlib.d.ts             |  2 +-
 3 files changed, 10 insertions(+), 71 deletions(-)

diff --git a/src/node/internal/internal_zlib.ts b/src/node/internal/internal_zlib.ts
index 0ef82df925a..50f8693a54e 100644
--- a/src/node/internal/internal_zlib.ts
+++ b/src/node/internal/internal_zlib.ts
@@ -103,26 +103,19 @@ function normalizeArgs(
 function wrapCallback(
   callback: CompressCallback<Error, Buffer>
 ): CompressCallback<string, ArrayBuffer> {
-  return (error: string | undefined, result: ArrayBuffer | undefined) => {
+  return (error: string | null, result: ArrayBuffer | undefined) => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-call
     queueMicrotask(() => {
-      callback(
-        error ? new Error(error) : undefined,
-        result ? Buffer.from(result) : undefined
-      );
+      if (error) {
+        callback(new Error(error));
+      } else {
+        // To avoid having a runtime assertion, let's use type assertion.
+        callback(null, Buffer.from(result as ArrayBuffer));
+      }
     });
   };
 }
 
-export function inflate(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function inflate(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function inflate(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
@@ -135,15 +128,6 @@ export function inflate(
   zlibUtil.zlib(data, options, zlibUtil.CONST_INFLATE, wrapCallback(callback));
 }
 
-export function unzip(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function unzip(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function unzip(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
@@ -156,15 +140,6 @@ export function unzip(
   zlibUtil.zlib(data, options, zlibUtil.CONST_UNZIP, wrapCallback(callback));
 }
 
-export function inflateRaw(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function inflateRaw(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function inflateRaw(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
@@ -182,15 +157,6 @@ export function inflateRaw(
   );
 }
 
-export function gunzip(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function gunzip(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function gunzip(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
@@ -203,15 +169,6 @@ export function gunzip(
   zlibUtil.zlib(data, options, zlibUtil.CONST_GUNZIP, wrapCallback(callback));
 }
 
-export function deflate(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function deflate(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function deflate(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
@@ -224,15 +181,6 @@ export function deflate(
   zlibUtil.zlib(data, options, zlibUtil.CONST_DEFLATE, wrapCallback(callback));
 }
 
-export function deflateRaw(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function deflateRaw(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function deflateRaw(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
@@ -250,15 +198,6 @@ export function deflateRaw(
   );
 }
 
-export function gzip(
-  data: ArrayBufferView | string,
-  callback: CompressCallback<Error, Buffer>
-): void;
-export function gzip(
-  data: ArrayBufferView | string,
-  options: ZlibOptions,
-  callback: CompressCallback<Error, Buffer>
-): void;
 export function gzip(
   data: ArrayBufferView | string,
   optionsOrCallback: ZlibOptions | CompressCallback<Error, Buffer>,
diff --git a/src/node/internal/internal_zlib_base.ts b/src/node/internal/internal_zlib_base.ts
index d7e63b5372c..1744322424d 100644
--- a/src/node/internal/internal_zlib_base.ts
+++ b/src/node/internal/internal_zlib_base.ts
@@ -349,7 +349,7 @@ export class ZlibBase extends Transform {
   public _defaultFlushFlag: number;
   public _finishFlushFlag: number;
   public _defaultFullFlushFlag: number;
-  public _info: unknown;
+  public _info: boolean;
   public _handle: ZlibHandleType | null = null;
   public _writeState = new Uint32Array(2);
 
@@ -430,7 +430,7 @@ export class ZlibBase extends Transform {
     this._defaultFlushFlag = flush;
     this._finishFlushFlag = finishFlush;
     this._defaultFullFlushFlag = fullFlush;
-    this._info = opts && opts.info;
+    this._info = Boolean(opts?.info);
     this._maxOutputLength = maxOutputLength;
   }
 
diff --git a/src/node/internal/zlib.d.ts b/src/node/internal/zlib.d.ts
index 0aade4d9feb..f46e711bb84 100644
--- a/src/node/internal/zlib.d.ts
+++ b/src/node/internal/zlib.d.ts
@@ -3,7 +3,7 @@ import { owner_symbol, type Zlib } from 'node-internal:internal_zlib_base';
 export function crc32(data: ArrayBufferView, value: number): number;
 
 export type CompressCallback<ErrT, BufT> = (
-  error?: ErrT,
+  error: ErrT | null,
   result?: BufT
 ) => void;