What causes "create64 is not supported in Worker shim" in DIYgod/RSSHub?

Use h64ToString on the fully concatenated input instead of create64().update().digest().

DIYgod/RSSHub · error · Error

create64 is not supported in Worker shim

Error message

create64 is not supported in Worker shim

What it means

Thrown by the Workers shim for xxhash-wasm when create64 is called. create64 returns a streaming XXHash<bigint> object (update/digest) that the shim cannot provide without WASM, so it aborts. The shim intentionally supports only the stateless h64ToString fallback used by cache.ts.

Solutions

Use h64ToString on the fully concatenated input instead of create64().update().digest().
Move the streaming-hash logic out of the Worker bundle into the Node-only entry.
If only a 32-bit stream is needed, use create32 which IS implemented in the shim (lib/shims/xxhash-wasm.ts:37).

Example fix

// before
const h = (await xxhash()).create64(seed);
for (const c of chunks) h.update(c);
const digest = h.digest();
// after
const h = (await xxhash()).create32(seed);
for (const c of chunks) h.update(c);
const digest = h.digest();

Defensive patterns

Strategy: type-guard

Validate before calling

function canStream64(api: any): boolean {
  try { const h = api.create64(); return typeof h?.update === 'function'; } catch { return false; }
}

Type guard

const isCreate64Usable = (api: XXHashAPI): boolean => {
  try { api.create64(); return true; } catch { return false; }
};

Try / catch

try {
  const h = (await xxhash()).create64(seed);
  chunks.forEach((c) => h.update(c));
  return h.digest();
} catch (e) {
  if (/not supported in Worker shim/.test((e as Error).message)) {
    return (await xxhash()).h64ToString(chunks.join(''), seed);
  }
  throw e;
}

Prevention

Avoid the streaming 64-bit API in code that runs in the Worker bundle - prefer stateless h64ToString.
For incremental hashing under Workers, use create32 which the shim supports.
Document the Worker-incompatible methods at the top of any module that uses xxhash.

When it happens

Trigger: Calling xxhash().create64(seed) and then .update()/.digest() in code that ends up in the Worker bundle. Any new code that streams chunks through a 64-bit hasher will hit this in the Worker environment.

Common situations: Introducing a code path that incrementally hashes large payloads with create64; pulling in a shared utility that picks create64 over h64ToString; cache key generation that was refactored to use the streaming API.

Related errors

AI-assisted analysis of DIYgod/RSSHub@bed535e087 (2026-08-12). Data as JSON: /api/errors/5a652da21de516b1. Report an issue: GitHub.

Appendix: source

Thrown at lib/shims/xxhash-wasm.ts:75

        // In practice, only h64ToString is used and it's called with await xxhash()
        h64: (_input: string, _seed?: bigint): bigint => {
            throw new Error('h64 is not supported in Worker shim, use h64ToString instead');
        },
        h64ToString: (input: string, _seed?: bigint): string => {
            // This needs to be sync to match the API, but we use a simple hash
            // The actual usage in cache.ts awaits xxhash() first, so this works
            let hash = 0n;
            const data = encoder.encode(input);
            for (const byte of data) {
                hash = ((hash << 5n) - hash + BigInt(byte)) & 0xff_ff_ff_ff_ff_ff_ff_ffn;
            }
            return hash.toString(16).padStart(16, '0');
        },
        h64Raw: (_inputBuffer: Uint8Array, _seed?: bigint): bigint => {
            throw new Error('h64Raw is not supported in Worker shim');
        },
        create64: (_seed?: bigint): XXHash<bigint> => {
            throw new Error('create64 is not supported in Worker shim');
        },
    };
}

export default xxhash;

View on GitHub (pinned to bed535e087)