How to use the @aws-sdk/util-buffer-from.fromArrayBuffer function in @aws-sdk/util-buffer-from

it("should accept string data", async () => {
    const hash = new Hash("md5");
    hash.update("");
    const { buffer } = await hash.digest();
    expect(fromArrayBuffer(buffer).toString("hex")).toBe(
      "d41d8cd98f00b204e9800998ecf8427e"
    );
  });

function castSourceData(toCast: SourceData, encoding?: string): Buffer {
  if (Buffer.isBuffer(toCast)) {
    return toCast;
  }

  if (typeof toCast === "string") {
    return fromString(toCast, encoding);
  }

  if (ArrayBuffer.isView(toCast)) {
    return fromArrayBuffer(toCast.buffer, toCast.byteOffset, toCast.byteLength);
  }

  return fromArrayBuffer(toCast);
}

function castSourceData(toCast: SourceData, encoding?: string): Buffer {
  if (Buffer.isBuffer(toCast)) {
    return toCast;
  }

  if (typeof toCast === "string") {
    return fromString(toCast, encoding);
  }

  if (ArrayBuffer.isView(toCast)) {
    return fromArrayBuffer(toCast.buffer, toCast.byteOffset, toCast.byteLength);
  }

  return fromArrayBuffer(toCast);
}

export function toUtf8(input: Uint8Array): string {
  return fromArrayBuffer(
    input.buffer,
    input.byteOffset,
    input.byteLength
  ).toString("utf8");
}

export function toBase64(input: Uint8Array): string {
  return fromArrayBuffer(
    input.buffer,
    input.byteOffset,
    input.byteLength
  ).toString("base64");
}