Mongodb - Modifying mongoose result modifies all document instead of one

AG_HIHI
November 21, 2022
101 views
0 votes
2 Answers

I have this function:

const getXNumberOfDocuments = async function getXNumberOfDocuments(
  page,
  results_per_page
) {
  /*************************************************** */
  results_per_page = parseInt(results_per_page);
  let x_number_of_documents = await Document.find()
    .populate([
      {
        path: "user",
        populate: {
          path: "profile",
          select: ["profileImageURL"],
        },
      },
    ])
    .limit(results_per_page)
    .skip(results_per_page * page)
    .lean();
  /*************************************************** */
  // I will stop this loop at i=0 by throwing an error
  // As you se below
  for (let i = 0; i < x_number_of_documents.length; i++) {
    console.log("🚀 ~ file: documentsServices.js ~ line 295 ~ i", i);
    // #BUG:
    // For some reason this changes
    // profileImageURL for i=0 and i=1 as well
    x_number_of_documents[i].user.profile.profileImageURL =
      "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!";
    // await s3_config.getImageReadSignedUrl(
    //   x_number_of_documents[i].user.profile.profileImageURL
    // );

    /*************************************************** */
    // I check all documents here
    // And I find that profileImageURL was modified in all of them
    // Even though I stopped the loop at i=0
    for (let j = 0; j < x_number_of_documents.length; j++) {
      console.log(
        "🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 j,",
        j
      );
      console.log(
        "🚀 ~ file: documentsServices.js ~ line 299 ~ x_number_of_documents[j].user.profile.profileImageURL",
        x_number_of_documents[j].user.profile.profileImageURL
      );
      console.log(
        "🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 "
      );
    }
    /*************************************************** */
    throw new Error("STOPPING LOOP AT i=0");
    /*************************************************** */
  }
  return x_number_of_documents;
};

It usually returns something like this:

 const response = [
    {
      user: {
        profile: {
          profileImageURL: "https://xxxxxxx.com/xxx.jpeg",
        },
      },
    },
    {
      user: {
        profile: {
          profileImageURL: "https://xxxxxxx.com/yyy.jpeg",
        },
      },
    },
    {
      user: {
        profile: {
          profileImageURL: "https://xxxxxxx.com/zzz.jpeg",
        },
      },
    },
  ];

I am trying to modify profileImageURL in each object:

for (let i = 0; i < x_number_of_documents.length; i++) {
  console.log("🚀 ~ file: documentsServices.js ~ line 295 ~ i", i);
  x_number_of_documents[i].user.profile.profileImageURL =
    "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!";
}

The problem is I find out that when i==0, instead of modifying profileImageURL ONLY the first object, it modifies it in all objects.

So when I break the loop after i==0, and log all the objects, I see that profileImageURL is the same in all of them:

🚀 ~ file: documentsServices.js ~ line 291 ~ x_number_of_documents.length 5
🚀 ~ file: documentsServices.js ~ line 295 ~ i 0

🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 j, 0
🚀 ~ file: documentsServices.js ~ line 299 ~ x_number_of_documents[j].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
3asba
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 j, 1
🚀 ~ file: documentsServices.js ~ line 299 ~ x_number_of_documents[j].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
3asba
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 j, 2
🚀 ~ file: documentsServices.js ~ line 299 ~ x_number_of_documents[j].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
3asba
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 j, 3
🚀 ~ file: documentsServices.js ~ line 299 ~ x_number_of_documents[j].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
3asba
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 j, 4
🚀 ~ file: documentsServices.js ~ line 299 ~ x_number_of_documents[j].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
3asba
🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀🚀 
🚀 ~ file: documents.js ~ line 204 ~ err Error: STOPPING LOOP AT i=0

Any idea what’s going on?

To better explain this, I simplified the snippets above:

x_number_of_documents[0].user.profile.profileImageURL =
  "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!";
console.log(
  "🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[0].user.profile.profileImageURL",
  x_number_of_documents[0].user.profile.profileImageURL
);
console.log(
  "🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[1].user.profile.profileImageURL",
  x_number_of_documents[1].user.profile.profileImageURL
);
console.log(
  "🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[2].user.profile.profileImageURL",
  x_number_of_documents[2].user.profile.profileImageURL
);
console.log(
  "🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[3].user.profile.profileImageURL",
  x_number_of_documents[3].user.profile.profileImageURL
);
console.log(
  "🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[4].user.profile.profileImageURL",
  x_number_of_documents[4].user.profile.profileImageURL
);

So even if I explicitly, changed the first object, this is the result:

🚀 ~ file: FILLING profileImageURL for i= 0
🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[0].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[1].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_ofdocuments[2].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[3].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!
🚀 ~ file: documentsServices.js ~ line 308 ~ x_number_of_documents[4].user.profile.profileImageURL THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!

So the final result is like this even though I explicitly only modified the first object!

const response = [
  {
    user: {
      profile: {
        profileImageURL:
          "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
      },
    },
  },
  {
    user: {
      profile: {
        profileImageURL:
          "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
      },
    },
  },
  {
    user: {
      profile: {
        profileImageURL:
          "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
      },
    },
  },
];

Strangely enough, if I modify the user instead of x_number_of_documents[0].user.profile.profileImageURL, it modified only the first object:

const response = [
  {
    user: "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
  },
  {
    user: {
      profile: {
        profileImageURL: "https://xxxxxxx.com/yyy.jpeg",
      },
    },
  },
  {
    user: {
      profile: {
        profileImageURL: "https://xxxxxxx.com/zzz.jpeg",
      },
    },
  },
];

And if I modify user.profile, I get the same original problem:

const response = [
  {
    user: {
      profile:
        "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
    },
  },
  {
    user: {
      profile:
        "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
    },
  },
  {
    user: {
      profile:
        "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!",
    },
  },
];

So this may have something to do with modifying values in embedded documents.

Answers

Chosen as BEST ANSWER
- AG_HIHI
- November 22, 2022 at 9:09 am
- 0 votes
0
Still no idea what's causing this weird bug, but I managed to solved it like this:
```
for (let i = 0; i < x_number_of_documents.length; i++) {
  x_number_of_documents[i].user = {
    ...x_number_of_documents[i].user,
    profile: {
      ...x_number_of_documents[i].user.profile,
      profileImageURL:
        "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM! " +
        i,
    },
  };
}
```

(Edit)

- PradeepYenkuwale
- November 21, 2022 at 12:20 pm
- 0 votes
0
If you want to update only first object of the array, you can break the loop by adding condition
```
for (let i = 0; i < x_number_of_documents.length; i++) {
  if (i > 0) break;
  console.log("🚀 ~ file: documentsServices.js ~ line 295 ~ i", i);
  x_number_of_documents[i].user.profile.profileImageURL =
    "THIS SHOULD ONLY BE MODIFIED FOR i=0 BUT IT IS MODIFIED FOR ALL OF THEM!";
}
```
and if the requirement is to update only first object of the array you don’t need loop through the array, you can do as follows
```
if(x_number_of_documents.length > 0){
    x_number_of_documents[0].user.profile.profileImageURL = "New URL";
}
```
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Mongodb – Modifying mongoose result modifies all document instead of one

Answers