How do you handle errors in IndexedDB operations?

Question

ICSM Computer · Answer

Handling 
errors in IndexedDB is essential for building a stable application, since
IndexedDB is asynchronous and relies on event-based operations.
Here’s how you can properly catch and handle errors:
1. Use onerror Events on Each Request
Every IndexedDB request (open, add, put,
get, etc.) has an onerror event.
Example:
const request = indexedDB.open("MyDB", 1);
request.onerror = function (event) {
    console.error("Failed to open DB:", event.target.error);
};
2. Transaction-Level Error Handling
You can also catch errors at the transaction level:
const tx = db.transaction("users", "readwrite");
tx.onerror = function (event) {
    console.error("Transaction failed:", event.target.error);
};
tx.onabort = function () {
    console.warn("Transaction aborted");
};
tx.oncomplete = function () {
    console.log("Transaction completed");
};
3. Request-Level Error Handling
Every operation (add, put, get, etc.) returns a request object you can attach
.onerror to:
const store = tx.objectStore("users");
const putRequest = store.put({ id: 1, name: "Alice" });
putRequest.onerror = function (event) {
    console.error("Put failed:", event.target.error);
};
4. Common Error Types
Error Name
When It Happens
QuotaExceededError
Exceeded storage quota
NotFoundError
Object store or index not found
ConstraintError
Duplicate key on .add() with existing key
TransactionInactiveError
Using a transaction after it’s complete
AbortError
Transaction aborted (manually or by error)
InvalidStateError
Misuse of IndexedDB APIs
5. Use try/catch with Promisified IndexedDB
If you're using async/await with Promises (like we discussed before), you can wrap the logic in
try/catch:
async function saveUser(user) {
    try {
        const db = await openDB("MyDB"); // Assume this is your wrapper
        const tx = db.transaction("users", "readwrite");
        await tx.objectStore("users").put(user);
        await tx.done;
        console.log("User saved");
    } catch (err) {
        console.error("Failed to save user:", err);
    }
}
Best Practices Summary
Tip
Why
Always handle request.onerror
Catch low-level operation issues
Use tx.onerror and tx.onabort
Catch broader transaction failures
Avoid silent failures
Log or notify user on data errors
Use try/catch if using Promises
Cleaner async error handling

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How do you handle errors in IndexedDB operations?

ICSM Computer

Can you answer this question?

1 Answers

1. Use `onerror` Events on Each Request

Example:

2. Transaction-Level Error Handling

3. Request-Level Error Handling

4. Common Error Types

5. Use `try/catch` with Promisified IndexedDB

Best Practices Summary

Liked By

Error Name	When It Happens
`QuotaExceededError`	Exceeded storage quota
`NotFoundError`	Object store or index not found
`ConstraintError`	Duplicate key on `.add()` with existing key
`TransactionInactiveError`	Using a transaction after it’s complete
`AbortError`	Transaction aborted (manually or by error)
`InvalidStateError`	Misuse of IndexedDB APIs

Tip	Why
Always handle `request.onerror`	Catch low-level operation issues
Use `tx.onerror` and `tx.onabort`	Catch broader transaction failures
Avoid silent failures	Log or notify user on data errors
Use `try/catch` if using Promises	Cleaner async error handling