How to get event.target.result in javascript indexdb typescript working?

Question

In my javascript/typescript project I have this code

        request.onupgradeneeded = (event: IDBVersionChangeEvent) => {
            console.log('idb onupgradeneeded firing');
            const db = event.target.result;
            //if (db != null) {
                //console.log(`Upgrading to version ${db.version}`);
                if (!request.result.objectStoreNames.contains(this.#name)) {
                    request.result.createObjectStore(this.#name, {keyPath: 'id', autoIncrement:true});
                }
            //}
        };

But the problem is this code

event.target.result;

Shows an underline saying Property 'result' does not exist on type 'EventTarget'.

How can I fix this in typescript?

Answer 1

There's not enough type information in handler callback type provided by dom Typescript library.

Probably you can define your own typing for indexedDB.open, but it looks much simpler to just downcast target manually:

const db = (event.target as IDBOpenDBRequest).result;

Or, as @kelsny suggested, use the original request object:

const db = request.result; // event.target === request