Firebase Functions [onCall]を使った関数でCORSが発生してしまう - Qiita

import * as functions from 'firebase-functions'; import { HttpsError } from 'firebase-functions/lib/providers/https'; export const exampleMethod = functions .region('asia-northeast1') .https.onCall(async (data, context) => { // hogehogeが空白でなければ中身をそのまま返し、空白ならエラーを投げる if (data.hogehoge !== '') { return { hogehoge: data.hogehoge } } else { throw new HttpsError('invalid-argument', 'hogehoge is required