如何获取Firebase Firestore生成的唯一ID？无需存入数据的实现需求

Got it, I totally get why you don't want to clutter your database with dummy data just to grab a unique ID—total waste of resources and extra cleanup work! Good news: Firestore has a built-in way to generate that ID without sending any data to the database at all.

The Solution: Use doc() Without an ID Parameter #

Firestore's doc() method, when called without passing a specific document ID, will instantly create a DocumentReference object with an auto-generated unique ID. No database write happens here—this is all client-side until you explicitly save data.

Here's how to implement it:

// Create a document reference with auto-generated ID (no database call yet)
const newDocRef = firestoreDB.collection("collection").doc();
// Extract the unique ID from the reference
const uniqueId = newDocRef.id;

console.log(uniqueId); // Your unique, pre-generated ID is ready to use!

How It Works #

Your original add() method actually does this under the hood: it first generates an ID with doc(), then writes the data to that document. By splitting these steps, you get the ID upfront without the unnecessary test data write.

Use the ID Later for Actual Writes #

When you're ready to save real data, just use the same DocumentReference to write to the database:

// When you're ready to persist your real data
newDocRef.set({ 
  data: "your actual meaningful data",
  // Any other fields you need
})
.then(() => console.log("Data saved successfully with pre-generated ID!"))
.catch(error => console.error("Error saving data: ", error));

This approach keeps your database clean and gives you full control over when data is written, while still getting that unique ID you need upfront.

内容的提问来源于stack exchange，提问作者Jama Mohamed