Using Concrete5 v8.4.2, I created a custom block for my site where, like the Image Slider, it displays a placeholder when in Edit Mode. When Block Cache is enabled in the Cache & Speed Settings, the public view is cached for the block and the edit mode view is no longer displayed.
The Image slider appears to get around this by using $btCacheBlockOutputForRegisteredUsers = false, but this is a high traffic site, so I really only want to disable the cached view when the page is in edit mode, not for all signed in users.
A previous question Concrete5 (5.7) - Don't cache page or current block on block error is close to what I want to achieve, but I am hoping that I can not render the cached view in Edit Mode, rather than expire the cache (on a trapped error). It would be bad for me to expire the cache, then end up caching the Edit Mode view. This question is also 18 months old and on a previous version of Concrete5, so I am hoping there is a better solution for my issue.
Rather than making the edit mode / view decision in php, you can do it in JavaScript. In the block JavaScript, you can test CCM_EDIT_MODE and only run the other scripts and show the normal block view if it is false, or replace the markup with an edit mode marker if it is true.