const blocks = [
  {
    "type": "section",
    "text": {
      "type": "mrkdwn",
      "text": "The uploaded file has finished processing!\n\n*Select an action or reaction:*"
    }
  },
  {
    "type": "divider"
  },
  {
    "type": "actions",
    "elements": [
      {
        "type": "button",
        "text": {
          "type": "plain_text",
          "text": "Delete",
          "emoji": true
        },
        "value": "delete"
      }
    ]
  }
];

const result = await web.files.uploadV2({
  channel_id: "C0123456789",
  blocks,
  file: "./index.js",
  filename: "code.js",
});

const result = await web.files.uploadV2({
  channel_id: "C0123456789",
  blocks,
  file_uploads: [
    {
      filename: "code.js",
      file: "./index.js",
    },
    {
      filename: "review.txt",
      content: "LGTM",
    },
  ],
});