Function digest

crypto/crypto.ts:205–257

* Polyfills stream support until the Web Crypto API does so: * @see https://github.com/wintercg/proposal-webcrypto-streams

(
      algorithm: DigestAlgorithm,
      data: BufferSource | AsyncIterable<BufferSource> | Iterable<BufferSource>,
    )

     * @see {@link https://github.com/wintercg/proposal-webcrypto-streams}
     */
    async digest(
      algorithm: DigestAlgorithm,
      data: BufferSource | AsyncIterable<BufferSource> | Iterable<BufferSource>,
    ): Promise<ArrayBuffer> {
      const { name, length } = normalizeAlgorithm(algorithm);

      assertValidDigestLength(length);

      // We delegate to WebCrypto whenever possible,
      if (
        // if the algorithm is supported by the WebCrypto standard,
        (WEB_CRYPTO_DIGEST_ALGORITHM_NAMES as readonly string[]).includes(
          name,
        ) &&
        // and the data is a single buffer,
        isBufferSource(data)
      ) {
        return await webCrypto.subtle.digest(algorithm, data);
      } else if (DIGEST_ALGORITHM_NAMES.includes(name as DigestAlgorithmName)) {
        if (isBufferSource(data)) {
          // Otherwise, we use our bundled Wasm implementation via digestSync
          // if it supports the algorithm.
          return stdCrypto.subtle.digestSync(algorithm, data);
        } else if (isIterable(data)) {
          return stdCrypto.subtle.digestSync(
            algorithm,
            data as Iterable<BufferSource>,
          );
        } else if (isAsyncIterable(data)) {
          const context = new DigestContext(name);
          for await (const chunk of data as AsyncIterable<BufferSource>) {
            const chunkBytes = toUint8Array(chunk);
            if (!chunkBytes) {
              throw new TypeError(
                "Cannot digest the data: A chunk is not ArrayBuffer nor ArrayBufferView",
              );
            }
            context.update(chunkBytes);
          }
          return context.digestAndDrop(length).buffer as ArrayBuffer;
        } else {
          throw new TypeError(
            // deno-lint-ignore deno-style-guide/error-message
            "data must be a BufferSource or [Async]Iterable<BufferSource>",
          );
        }
      }
      // (TypeScript type definitions prohibit this case.) If they're trying
      // to call an algorithm we don't recognize, pass it along to WebCrypto
      // in case it's a non-standard algorithm supported by the the runtime
      // they're using.
      return await webCrypto.subtle.digest(algorithm, data as BufferSource);
    },

    digestSync(
      algorithm: DigestAlgorithm,