Perform an async action in beforeChange?

[giorgitus]

I don't know if it has already been asked.

It is possible to call an asynchronous method inside the beforChange?

I need to do some server-side checks on the read-only status of some fields.

Until now I used the synchronous call of XMLHttpRequest but this method is deprecated.
https://xhr.spec.whatwg.org/#sync-warning

Is it possible to return a promise from the beforeChange method?
Or is there some other way to have asynchronous handling of the beforeChange method.

Thank you

[mrpiotr-dev]

Hi @giorgitus,
It's possible to adjust before/after-change hooks to postpone inserting changes into the dataset. Please look at the following example: https://jsfiddle.net/pg20oaf7/

[giorgitus]

This is exactly the problem. In the afterchange (where I send many other events)the data is still the previous one.
The afterchange must execute after the beforechange has completely finished.
Is it possible in any way?

[mrpiotr-dev]

In the above example, I used the source argument to control data-changing flow.
A source-related condition will block editing using editors in beforeChange (which makes this behavior a non-optimistic UI). Next beforeChange "simulates" client-server communication. As a callback, I use setDataAtCell with a custom source to catch that change from other sources than Editor.
Could you fork my example from jsfiddle and adjust it more or less to what you would like to achieve? That would help us to suggest a correct approach that would be best to use in your project.

[giorgitus]

Thank you so much for the answare.

I want to stop the change in the beforeChange if there is a server side condition. Here it is the example
https://jsfiddle.net/gtoniolo/vL4mod1k/

In this example I want to prevent the field from changing if the column number is even. Unfortunately I know it's even only on the server side.

[mrpiotr-dev]

If you know that condition on the server-side, that means you have to pass all changes through the server-side and block all built-in edit action on the client-side: https://jsfiddle.net/nfkoxze1/.

As I mentioned - you can use the source argument to control and recognize when Handsontable should apply changes and when the table should send them to the server-side.

[giorgitus]

Sorry for the late reply. This is the solution. Thank you very much. It works like a charm.