@sheetom/wasm

Explicit, ESM-only WebAssembly backend for SheetOM.

import { createSheetOM } from "@sheetom/wasm";

const { CSSStyleSheet } = await createSheetOM();
const sheet = new CSSStyleSheet();
sheet.insertRule(".card { color: red; }");

The default factory resolves sheetom_wasm_bg.wasm relative to the package module, initializes it once per JavaScript realm, and shares concurrent calls:

const [first, second] = await Promise.all([createSheetOM(), createSheetOM()]);
console.log(first === second); // true

Serve the .wasm asset with Content-Type: application/wasm to use streaming instantiation. The loader falls back to buffered instantiation when the server uses another MIME type. It requires neither WASI nor cross-origin isolation and works in a module worker through the same async factory.

Pass a URL, Response, ArrayBuffer, or precompiled WebAssembly.Module to create an independent backend:

const response = await fetch(new URL("./engine.wasm", import.meta.url));
const isolated = await createSheetOM(response);

Each independent facade has distinct class identity, so use constructors from the same returned object for instanceof. Unexpected WebAssembly traps poison only that backend and become SheetOMWasmBindingError errors; ordinary CSS validation and Resource Budget errors keep the same transactional behavior as the native package.

The package never acts as an automatic fallback for sheetom, never installs native binaries, and does not modify globalThis. Its JavaScript imports are fully static, so Vite, esbuild, Rollup, and Webpack can analyze the complete runtime. The external .wasm asset must remain beside the emitted SheetOM module (or be relocated by the bundler while rewriting new URL(...)); it is not embedded into JavaScript. See the root project documentation for the full API, resource-budget, and compatibility contracts.