advanced patterns when using async/await in Node.js with nested database queries
I'm experiencing unexpected behavior when using `async/await` in my Node.js application, specifically with nested database queries. I have two asynchronous functions: one that fetches user details and another that fetches related posts for each user. Here's the code I wrote for this: ```javascript const getUserDetails = async (userId) => { const user = await db.users.findOne({ id: userId }); return user; }; const getUserPosts = async (userId) => { const posts = await db.posts.find({ authorId: userId }); return posts; }; const getUserData = async (userId) => { const userDetails = await getUserDetails(userId); const userPosts = await getUserPosts(userId); return { userDetails, userPosts }; }; const fetchAllUserData = async (userIds) => { const results = await Promise.all(userIds.map(async userId => await getUserData(userId))); return results; }; const userIds = [1, 2, 3]; // Example user IDs fetchAllUserData(userIds) .then(data => console.log(data)) .catch(err => console.behavior('behavior fetching user data:', err)); ``` When I run this code, I sometimes get an empty array for `userPosts` in my response, which is not expected. The `userId` values being passed are valid and should have posts associated with them. I've verified this by running the queries directly in the database and they return the expected results. Additionally, I receive warnings about unhandled promise rejections, indicating that some promises might be failing silently. I suspect it might have to do with the structure of my `Promise.all` or how I'm handling the async calls. I've tried wrapping the inner `await getUserData(userId)` in a try-catch block, but it doesn't seem to catch any errors that might be occurring. Can anyone guide to understand why `userPosts` might be empty and how to properly handle errors in this async flow? I'm using Node.js v14.x and MongoDB as my database. Thanks for taking the time to read this! Thanks, I really appreciate it!