Dexie.js | A Minimalistic Wrapper for IndexedDB | Storage library

Table.defineClass() was an old feature in Dexie 1.x for code completion only - no enforcements. The method should have been deprecated. But the functionality you need can be implemented using a DBCore middleware or creating/updating hooks. DBCore middlware would be the most performant solution as it does not need to verify existing data.

Below is a dry coded full example. Please test and reply if it works. It should support String, Number, Boolean, Array, Object, Set, Map, ArrayBuffer, Uint8Array, etc... and even custom classes. If anyone wants to make a package of this code, please go ahead! I think it could be a nice addon to dexie:

I'm not sure what you mean with "restore" but I think you mean to import data into IndexedDB? Or did you mean that IndexedDB is the backup and "restore" for putting it back into another database?

I base the rest of my answer on the assumption that "restore" is importing data into indexeddb.

The only way to know how the system would perform when adding millions of key/value (blob) based rows would be to test it. I would suggest you import the rows in chunks of maybe 1000 each and show a progress bar for each imported chunk. Use bulkAdd() or bulkPut() methods to import each chunk. Make sure not to do the entire import in a single transaction because that could probably starve the system and block indexeddb for too long. But by using the bulk-methods each chunk would use a single transaction at least (which is also important - one transaction per 1000 records would probably be fine - but if you test this, try different chunk sizes to find the optimal speed!).

Also don't know what the user can expect in terms of waiting time. Can it be performed in the background while user can use your app in online mode? If so, it the user could probably accept longer import-time than if the user would have to wait for the entire data to be imported.

You would also need to look at the StorageManager API and ask your user for permission to store large amounts of durable data. You can read page about it in dexie docs also.

You would probably want a background worker to fetch the data and perform the bulk operations - create a service worker that does the job. Either use response.blob() and pass it to dexie-export-import. You could also try the ReadableStream api to download chunks of data. Letting a worker do this download and import will perform faster and not affect the application performance while importing.

Dexie-export-import does almost exactly what I am suggesting here - imports the rows in chunks into indexeddb, but if using it you would need to let your service endpoint send JSON that is compatible with dexie-export-import where blobs are Baset64 encoded. But since your data is only keys and blobs, you could benefit from having your own binary format and do the bulkAdd() yourself without this addon.

Regarding your last question: to my knowledge, there wouldn't be so much difference between using number or strings as keys. Long strings would be slower but short strings probably perform equal to numbers (correct me someone if this isn't true!). You would need to test to really know.

If you will perform some test on this, please let me know what your results were ;)

The equals method is a strict equality test, so if id is a number type in indexedDB, then the string type returned from localStorage won't match, because of the different types. And localStorage only stores strings.

For this reason, it's common to see JSON.parse used when retrieving data from localStorage, to convert serialized data :

Try inspecting the call stack. I know it can be long until you reach a frame within your application code, but the failing call should be there!

I think you're missing to set Dexie.dependencies.IDBKeyRange also.

Fake-indexeddb recommends to do the following to integrate fake-indexeddb in node:

Thank you @kaiido for link this is an answer -=> https://github.com/dfahlander/Dexie.js/issues/789

Please let your promise-using functions return a promise so you can chain the calls to them.

Regarding calling delete within Collection.each(), it is not possible because Collection.each() is readonly unless you call it from a readwrite transaction. If you want to modify things within the iteration, use Collection.modify() instead of Collection.each(). This is described in the Notes section for Collection.each: https://dexie.org/docs/Collection/Collection.each()#notes

Please set receivers initial value as array

To make a value or object reactive in Vue it needs to be initialised properly, generally this is either as a prop, a data property or a computed value.

Vue is not seeing changes to your db variable because it hasn't been initialised as one of these.

For an array of table data you can initialise it like this: