如何在 Firestore 的父 map 字段中添加新的 map 字段？

Question

I want to add a new map field inside another map field. My data structure looks like this:

I want to add a 'field b' after 'field a' inside 'Filed 1' (pardon my typo).

my code looks like this

 const collsRef = doc(db, "collections", collectionUid); // get the right document
 await setDoc(collsRef, { sellectData }, { merge: true });

but not only this is giving me an error, I believe this code would only add a new field at the same level as 'Filed 1'

the data type triggering the unsupported field value error is an JS object like so – do I need to parse it before comiting it to the db?

I've blanked out data and left the structure and syntax because it contained personal sensitive data. I hope it's enough to explain the problem.

many thanks in advance

Answer 1

I'm not sure what the sellectData structure looks like but you have to construct an object that has the same structure from Firestore. See sample code below:

const collsRef = doc(db, "collections", collectionUid);

let sellectData = {
  "field b": { "key b" : "value b" }
}

await setDoc(collsRef, { 
  "Filed 1": sellectData
}, { merge: true });

This would result in (already corrected your typo):

---

Update:

You have two options to set the object key as a variable.

You need to make the object first, then use [] to set it.:

let key = "Field 1";
let sellectData = {
  "field b": { "key b" : "value b" }
}

await setDoc(collsRef, {
  [key]: sellectData
}, { merge: true });

Or, by contructing the object itself.

let key = "Field 1";

let sellectData = {
  [key] : { "field b": 
    { "key b" : "value b" }
  }
}

// Remove the curly brackets `{}` in this case.
await setDoc(collsRef, 
  sellectData, 
  { merge: true });

---

For more information, see Update fields in nested objects .