simplify createDataView

Author: gfx

src/Decoder.ts

@@ -2,7 +2,7 @@ import { prettyByte } from "./utils/prettyByte";
 import { ExtensionCodec, ExtensionCodecType } from "./ExtensionCodec";
 import { getInt64, getUint64, UINT32_MAX } from "./utils/int";
 import { utf8Decode } from "./utils/utf8";
-import { createDataView, ensureUint8Array } from "./utils/typedArrays";
+import { ensureUint8Array } from "./utils/typedArrays";
 import { CachedKeyDecoder, KeyDecoder } from "./CachedKeyDecoder";
 import { DecodeError } from "./DecodeError";
 import type { ContextOf } from "./context";
@@ -244,8 +244,9 @@ export class Decoder<ContextType = undefined> {
   }
 
   private setBuffer(buffer: ArrayLike<number> | ArrayBufferView | ArrayBufferLike): void {
-    this.bytes = ensureUint8Array(buffer);
-    this.view = createDataView(this.bytes);
+    const bytes = ensureUint8Array(buffer);
+    this.bytes = bytes;
+    this.view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
     this.pos = 0;
   }
 

src/utils/typedArrays.ts

@@ -1,4 +1,4 @@
-function isArrayBuffer(buffer: unknown): buffer is ArrayBuffer | SharedArrayBuffer {
+function isArrayBufferLike(buffer: unknown): buffer is ArrayBufferLike {
   return (
     buffer instanceof ArrayBuffer || (typeof SharedArrayBuffer !== "undefined" && buffer instanceof SharedArrayBuffer)
   );
@@ -11,19 +11,10 @@ export function ensureUint8Array(
     return buffer;
   } else if (ArrayBuffer.isView(buffer)) {
     return new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength);
-  } else if (isArrayBuffer(buffer)) {
+  } else if (isArrayBufferLike(buffer)) {
     return new Uint8Array(buffer);
   } else {
     // ArrayLike<number>
     return Uint8Array.from(buffer);
   }
 }
-
-export function createDataView(buffer: ArrayLike<number> | ArrayBufferView | ArrayBuffer): DataView<ArrayBufferLike> {
-  if (buffer instanceof ArrayBuffer) {
-    return new DataView(buffer);
-  }
-
-  const bufferView = ensureUint8Array(buffer);
-  return new DataView(bufferView.buffer, bufferView.byteOffset, bufferView.byteLength);
-}