Bug: Min / Max Empty Table

[Kylar182]

I tried the new Min / Max Key / Index feature and it seems to have an issue when the table is empty. Says the Key is Null and throws an exception.

[mcbride-clint]

I was able to move the error up to the c# level, so the JS just returns null, but then System.Text.Json cannot deserialize null to string or int or whatever type you want.

Wrapping the call in a try/catch works and just return default whenever that happens. But I don't like relying on exceptions to guide the flow even though this should be a uncommon occurrence.

Making _jsRuntime.InvokeAsync return an JsonElement type works and can then check for ValueType.Null and return default.

[Kylar182]

Any news on this?

[mcbride-clint]

Still awaiting the pull request to be approved. @amuste

[amuste]

I have already approved the pullrequest

[Kylar182]

@mcbride-clint is the Observable / Async Code different on this method? It's not letting me call 2 queries simultaneously. It says the request didn't finish. I can reproduce it in the test repo if you'd like.

[mcbride-clint]

I was able to reproduce it I think. I assume you mean this:

    var indexMaxTask = GridColumnDataIndexedDb.GetMaxIndex<string>("TableFieldDtos", "attachedProperty");

    var indexMinTask = GridColumnDataIndexedDb.GetMinIndex<string>("TableFieldDtos", "attachedProperty");

    var indexMax = await indexMaxTask;

    var indexMin = await indexMinTask;

There shouldn't be anything different. I have never used RxJs so I just mimicked what I had seen in the other cursor range selects. There must be a variable or id that is making it use the same cursor when running more than one at a time.

[mcbride-clint]

I think I found the issue. Line 932

                    if (dbIndex) {
                        // Search By Index
                        const index = objectStore.index(dbIndex);
                        cursorRequest = index.openCursor(null, extentType);
                    } else {
                        // Search By Key
                        cursorRequest = objectStore.openCursor(null, extentType);
                    }

I never declared cursorRequest so it must be being hoisted by Javascript to be global and and being shared between the requests. It looks like putting let cursorRequest right above the line will fix it but I know @amuste changed all of his declarations from let to const in the past. I'm not super well versed in JS but is there any issue in using let?

[noelrv]

return new Rx.Observable((getReqObserver) => {
                        let cursorRequest = null;
                        if (dbIndex) {
                            // Search By Index
                            const index = objectStore.index(dbIndex);
                            cursorRequest = index.openCursor(null, extentType);

It makes sense to use let for cursorRequest; const can't be used as it is assigned a value in more than one occasion.

[mcbride-clint]

Thanks for the feedback. I have mostly used Internet Explorer so let and const are new to me. definitely an improvement over just var from what I can tell.