Clean up some hash typings.

lib/getHashDigest.ts

@@ -1,4 +1,4 @@
-import type { Hash, BinaryToTextEncoding } from "crypto";
+import type { BinaryToTextEncoding } from "crypto";
 
 const baseEncodeTables = {
   26: "abcdefghijklmnopqrstuvwxyz",
@@ -95,7 +95,7 @@ export default function getHashDigest(
       }
     }
 
-    hash = new BatchedHash(createXXHash64() as unknown as Hash);
+    hash = new BatchedHash(createXXHash64());
   } else if (algorithm === "md4") {
     if (createMd4 === undefined) {
       createMd4 = require("./hash/md4").create;
@@ -105,7 +105,7 @@ export default function getHashDigest(
       }
     }
 
-    hash = new BatchedHash(createMd4() as unknown as Hash);
+    hash = new BatchedHash(createMd4());
   } else if (algorithm === "native-md4") {
     if (typeof crypto === "undefined") {
       crypto = require("crypto");

lib/hash/BatchedHash.ts

@@ -1,12 +1,17 @@
-import type { Hash, Encoding, BinaryToTextEncoding } from "crypto";
+import type { Encoding, BinaryToTextEncoding } from "crypto";
 import { MAX_SHORT_STRING } from "./wasm-hash";
 
+export interface IHashLike {
+  update(data: string | Buffer, inputEncoding?: Encoding): this;
+  digest(encoding?: BinaryToTextEncoding): string | Buffer;
+}
+
 export class BatchedHash {
   public string?: string;
   public encoding?: Encoding;
-  public readonly hash: Hash;
+  public readonly hash: IHashLike;
 
-  constructor(hash: Hash) {
+  constructor(hash: IHashLike) {
     this.string = undefined;
     this.encoding = undefined;
     this.hash = hash;

lib/hash/wasm-hash.ts

@@ -1,5 +1,7 @@
 import { BinaryToTextEncoding } from "crypto";
 
+import type { IHashLike } from "./BatchedHash";
+
 /*
 	MIT License http://www.opensource.org/licenses/mit-license.php
 	Author Tobias Koppers @sokra
@@ -11,7 +13,7 @@ import { BinaryToTextEncoding } from "crypto";
 // ~3 makes sure that it's always a block of 4 chars, so avoid partially encoded bytes for base64
 export const MAX_SHORT_STRING: number = Math.floor((65536 - 64) / 4) & ~3;
 
-export class WasmHash {
+export class WasmHash implements IHashLike {
   /**
    * @param {WebAssembly.Instance} instance wasm instance
    * @param {WebAssembly.Instance[]} instancesPool pool of instances
@@ -200,20 +202,23 @@ export const create = (
   chunkSize: number,
   digestSize: number
 ) => {
+  let result: WasmHash | undefined;
   if (instancesPool.length > 0) {
-    const old = instancesPool.pop();
+    result = instancesPool.pop();
 
     // old is possibly undefined
     // protect reset call here
-    old && old.reset();
+    result?.reset();
+  }
 
-    return old;
-  } else {
+  if (result === undefined) {
     return new WasmHash(
       new WebAssembly.Instance(wasmModule),
       instancesPool,
       chunkSize,
       digestSize
     );
   }
+
+  return result;
 };