core: cache the whole-array SharedRows view

view() allocated a fresh typed array on every access (and row() a second
subarray); the view is now built once per descriptor in update().

Amp-Thread-ID: https://ampcode.com/threads/T-01a0b2dd-db32-712d-99ce-12ce4a86d979
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

core/index.js

@@ -1,6 +1,8 @@
 const views = Object.freeze({ f32: Float32Array, u32: Uint32Array, i32: Int32Array });
 
 export class SharedRows {
+  #view;
+
   constructor(buffer, descriptor) {
     if (!(buffer instanceof SharedArrayBuffer)) throw new TypeError("ROWS_DESCRIPTOR");
     this.buffer = buffer;
@@ -11,6 +13,8 @@ export class SharedRows {
     if (!views[descriptor.format] || descriptor.name !== (this.descriptor?.name ?? descriptor.name))
       throw new TypeError("ROWS_DESCRIPTOR");
     this.descriptor = Object.freeze(descriptor);
+    const View = views[descriptor.format];
+    this.#view = new View(this.buffer, descriptor.offset, descriptor.bytes / View.BYTES_PER_ELEMENT);
     return this;
   }
 
@@ -18,10 +22,8 @@ export class SharedRows {
   get rows() { return this.descriptor.rows; }
   get stride() { return this.descriptor.stride; }
   get format() { return this.descriptor.format; }
-  get view() {
+  /** One typed view over the whole array; replaced only when the descriptor changes. */
-    const View = views[this.format];
+  get view() { return this.#view; }
-    return new View(this.buffer, this.descriptor.offset, this.descriptor.bytes / View.BYTES_PER_ELEMENT);
-  }
 
   row(index) {
     if (!Number.isInteger(index) || index < 0 || index >= this.rows) throw new RangeError("ROW_RANGE");