Question 171485 in Javascript Question posted in
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Can Promise.all() return nested objects w/ two objs?

I want to, first of all, fetch the data of a user, then in that user’s history object, I wanna fetch the data of each user there. the problem is, I want to kind of add the amount from the history object together with the user’s data fetched as an object or array, but I get an empty object.

import users from "@/models/users";
import { NextResponse } from "next/server";
import bcrypt from "bcryptjs";
import dbConnect from "@/util/mongodb";

export async function GET(req, { params }) {
  await dbConnect();
  try {
    const data = await users.findOne({ username: params.id }, { pin: 0 });

    const history = await Promise.all(
      data.history.map((user) => {
        const us = users.findOne(
          { _id: user.id },
          { firstname: 1, username: 1, lastname: 1 }
        );

        return us;
        //I get an empty object when i return {user: us, amount: user.amount}
      })
    );
    return NextResponse.json(history, { status: 200 });
  } catch (err) {
    return NextResponse.json(err, { status: 500 });
  }
}
Tags:

2

Answers


  1. 0

    I get an empty object when i return {user: us, amount: user.amount}

    The problem is that us is again a promise (which serialises to an empty JSON object), you would need to wait for it:

    const history = await Promise.all(
  data.history.map(async (user) => {
    const us = await users.findOne(
//             ^^^^^
      { _id: user.id },
      { firstname: 1, username: 1, lastname: 1 }
    );

    return {user: us, amount: user.amount}
  })
);
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  2. 0

    The reason you’re getting an empty object when you try to return { user: us, amount: user.amount } is that the users.findOne() method in your code is missing an await keyword, causing the function to return a promise instead of the actual user data. To fix this issue, you need to await the users.findOne() method to retrieve the user data correctly.

    Here’s the updated code snippet with the necessary changes:

    import users from "@/models/users";
import { NextResponse } from "next/server";
import bcrypt from "bcryptjs";
import dbConnect from "@/util/mongodb";

export async function GET(req, { params }) {
  await dbConnect();
  try {
    const data = await users.findOne({ username: params.id }, { pin: 0 });

    const history = await Promise.all(
      data.history.map(async (user) => {
        const us = await users.findOne(
          { _id: user.id },
          { firstname: 1, username: 1, lastname: 1 }
        );

        return { user: us, amount: user.amount };
      })
    );

    return NextResponse.json(history, { status: 200 });
  } catch (err) {
    return NextResponse.json(err, { status: 500 });
  }
}

    I added the async keyword to the data.history.map() callback function, allowing us to use await inside it. By adding await before users.findOne(), you ensure that the function waits for the user data to be fetched before continuing to the next iteration.

    Now, when you return { user: us, amount: user.amount }, it should include the user object fetched from users.findOne() and the corresponding amount from the history object.

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