npm install @google/clasp -g #claspのインストール（node.jsを使ってる）
clasp login #ログイン（勝手にブラウザーが立ち上がった）
mkdir slack-mail-notification #ディレクトリを作成
cd slack-mail-notification #ディレクトリに移動
clasp create slack-mail-notification #slack-mail-notificationと言うapp scriptを作成
? Create which script? #スクリプトの種類を聞かれる
> api #どれを選べば良いか分からなかったが雰囲気でAPIを選択
Nested clasp projects are not supported.

clasp clone [Script ID]

git init #Gitのセットアップ
npm i -S @types/google-apps-script #型の設定
mv Code.js Code.ts #tsに変更
touch .gitignore

node_modules

const recipient: string = "kaibatsu35.7m45@gmail.com";
const subject: string = "Hallo World";
const body: string = "This is a test message from GAS";

GmailApp.sendEmail(recipient, subject, body);

function getEmailList(
  SpreadSheetID: string
): { address: string; name: string }[] {
  let mailData = [];
  const sheet = SpreadsheetApp.openById(SpreadSheetID);
  const data = sheet.getDataRange().getValues();
  data.shift();
  data.forEach((data) => {
    mailData.push({
      address: data[1],
      name: data[0],
    });
  });
  return mailData;
}

function doPost(e) {
  const emailList = getEmailList(SpreadSheetID);
  const slackData = JSON.parse(e);
  emailList.forEach((emailData) => {
    SendEmail(
      emailData.address,
      `A message from ${slackData.event.user}`,
      `${slackData.event.user}: ${slackData.event.text}`
    );
    Logger.log(`Sent an email to ${emailData.name}`);
  });
  return ContentService.createTextOutput(JSON.stringify(e));
}

function doPost(e) {
  const emailList = getEmailList(SpreadSheetID);
  const slackData = JSON.parse(e.postData.getDataAsString());
  emailList.forEach((emailData) => {
    SendEmail(
      emailData.address,
      `A message from ${slackData.event.user}`,
      `${slackData.event.user}: ${slackData.event.text}`
    );
    Logger.log(`Sent an email to ${emailData.name}`);
  });
  const response = {
    challenge: e,
  };
  return ContentService.createTextOutput(JSON.stringify(response)).setMimeType(
    ContentService.MimeType.JSON
  );
}

function getUserInfo(id: string) {
  const slackUsersApi: string = "https://slack.com/api/users.profile.get";
  const params: object = {
    method: "post",
    headers: {
      Authorization: `Bearer ${PropertiesService.getScriptProperties().getProperty(
        "slackOAthToken"
      )}`,
    },
    payload: {
      user: id,
    },
  };
  const response = JSON.parse(
    UrlFetchApp.fetch(slackUsersApi, params).getContentText()
  );
  return response;
}

 function doPost(e) {
   const emailList = getEmailList(SpreadSheetID);
   const slackData = JSON.parse(e.postData.getDataAsString());
+  const postedUser: string = getUserInfo(slackData.event.user).ok
+    ? "display_name_normalized" in getUserInfo(slackData.event.user).profile
+      ? getUserInfo(slackData.event.user).profile.display_name_normalized
+      : getUserInfo(slackData.event.user).profile.real_name_normalized
+    : "unknown";
   emailList.forEach((emailData) => {
     SendEmail(
       emailData.address,
-      `A message from ${slackData.event.user}`,
-      `${slackData.event.user}: ${slackData.event.text}`
+      `A message from ${postedUser}`,
+      `${postedUser}: ${slackData.event.text}`
     );
     Logger.log(`Sent an email to ${emailData.name}`);
   });
   const response = {
     challenge: e,

function SendEmail(recipient: string, subject: string, body: string) {
-  GmailApp.sendEmail(recipient, subject, body, {
+  MailApp.sendEmail(recipient, subject, body, {
     name: "Slack Mail Notification Bot",
   });
 }

function addEmail(
  sheet: GoogleAppsScript.Spreadsheet.Sheet,
  name: string,
  address: string
): { error: boolean; message?: string } {
  let error = false;
  let message = "";
  const textFinder: GoogleAppsScript.Spreadsheet.TextFinder = sheet.createTextFinder(
    address
  );
  if (!!sheet.createTextFinder(address).findAll().length) {
    error = true;
    message += "既に登録済みです。";
  }
  if (!error) {
    sheet.appendRow([name, address, new Date().toLocaleDateString("ja-jp")]);
  }
  return {
    error: error,
    message: message,
  };
}

 function doPost(e) {
   if (e.postData.type == "application/json") {
     const slackData: slackEventResponse = JSON.parse(
       e.postData.getDataAsString()
     );
-    if (slackData.token == slackAuthToken)
+    if (slackData.token == slackVerificationToken)
       if (slackData.event.type == "app_mention") {
         Logger.log("App mentioned");
         appMentioned(slackData);
       }
+  } else if (
+    e.postData.type == "application/x-www-form-urlencoded" &&
+    e.parameter.token == slackVerificationToken
+  ) {
+    return slashCommand(e);
   }
 }

function subscribe(e) {
  const slackData: Readonly<slashCommandResponse> = e.parameter;
  console.info(e);
  console.info(e.parameter);
  const userInfo = getUserInfo(slackData.user_id);
  const name: string =
    userInfo.profile.display_name_normalized == ""
      ? userInfo.profile.display_name_normalized
      : userInfo.profile.real_name_normalized;
  const address: string = userInfo.profile.email;
  const addEmailStatus = addEmail(sheet, name, address);
  const message: string = addEmailStatus.error
    ? addEmailStatus.message
    : `${address} を登録しました`;
  const response = { text: message };
  return ContentService.createTextOutput(JSON.stringify(response)).setMimeType(
    ContentService.MimeType.JSON
  );
}

function deleteEmail(
  sheet: GoogleAppsScript.Spreadsheet.Sheet,
  address: string
): { error: boolean; message?: string } {
  let error = false;
  let message = "";
  const matchCell: GoogleAppsScript.Spreadsheet.Range[] = sheet
    .createTextFinder(address)
    .findAll();
  if (!matchCell.length) {
    error = true;
    message += "このメールアドレスは登録されていません";
  }
  if (!error) {
    sheet.deleteRow(matchCell[0].getRow());
    SendEmail(
      address,
      "メールアドレス登録解除完了",
      `登録解除が完了しました。`
    );
  }
  return {
    error: error,
    message: message,
  };
}

const params: GoogleAppsScript.URL_Fetch.URLFetchRequestOptions = {
    method: "post",
    headers: {
        Authorization: `Bearer ${slackAuthToken}`
    },
    payload: {
        channel: id,
        blocks: JSON.stringify(blocks)
    }
}
UrlFetchApp.fetch(slackCreateMessageAPI, params).getContentText()
const returnObj = { blocks: blocks }
return ContentService.createTextOutput(
    JSON.stringify(returnObj)
).setMimeType(ContentService.MimeType.JSON)