"Cannot read properties of null (reading 'getInternalPath')"

[joshkel]

I'm sporadically getting the following error when I change object keys (not values):

TypeError: Cannot read properties of null (reading 'getInternalPath')
S.value
https://76uwry.csb.app/node_modules/jsoneditor/dist/jsoneditor.min.js:33:36942
eval
https://76uwry.csb.app/node_modules/jsoneditor/dist/jsoneditor.min.js:35:2194

See https://codesandbox.io/s/jsoneditor-debounced-error-76uwry for an example: Try changing hello. (This calls setValue extremely fast to demonstrate the problem.)

I believe that the problem is caused by a race condition: Edits are propagated with a 150ms delay (due to the use of debounce), so, if the editor receives a new value, the old value has been removed and no longer has the fields that the event handler expects it to have.

https://github.com/josdejong/jsoneditor/blob/v9.9.2/src/js/Node.js#L1649

I'm not sure if the correct fix is to cancel debounced events when a node is removed (e.g., Lodash's debounce has a cancel function; a similar idea could be added here) or make the events check for, e.g., this.parent == null.

[josdejong]

Thanks for reporting! I don't get the error you report, but when I change the interval in your example from 1000 to 10 I can get a similar error 'Uncaught TypeError: this.parent is null'.

I think you're right and this is because of the debounce. So basically, there are two competing changes: the external change, and the change being made by the user, and we could decide to let either of the two changes "win". I think we should go for the simplest solution, which probably is to make it effectively do nothing by checking if this.parent still exists (cancelling the debounce would be fine with me too, but the used debounce function currently does not have a cancel method).