Reduce unnecessary replotting on dashboard startup and on target variable switching #260
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app/server.R
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| @@ -131,14 +131,14 @@ server <- function(input, output, session) { | |||
| HOSP_CURRENT <- resolveCurrentHospDay() | |||
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| PREV_AS_OF_DATA <- reactiveVal(NULL) | |||
| AS_OF_CHOICES <- reactiveVal(NULL) | |||
| AS_OF_CHOICES <- reactiveVal(resolveCurrentHospDay()) | |||
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question: do we need to run resolveCurrentHospDay again, or can we use the recently-computed value from HOSP_CURRENT?
is the advantage of computing this as a reactive value that if a user leaves the dash open for long periods of time, they'll automatically see updates?
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It looks to me that the main goal of AS_OF_CHOICES being reactive is to be easy to update from child processes. It doesn't look like its reactive behavior will ever be triggered since as of choices will only change when the target variable changes, which causes the same replotting and recalculating that AS_OF_CHOICES would.
I think we're safe to make it into a global instead, but then we'll need to do out-of-environment assignment (<<-). Knowing that, do you have a preference one way or the other?
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hmmm I don't feel strongly about it -- a global vs some superfluous reactivity are probably equally annoying. that suggests, do whatever's easy :)
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Given that we should do a bigger refactor of the reactive behavior, I'm leaving this as-is and will create an issue.
The UI defines startup selection values globally, for all users
assigned to that Shiny session. Startup values are treated as constants,
so a hard-coded asof date won't update if the Shiny session persists (is
continually used) across a date boundary that would normally change the
default asof selection. Thus, we need to set the starting asof value on
a user-by-user basis so that it is recalculated when a new dashboard
instance is opened. To do that, set the initial asof value back to empty
("") and run an updater observe on dashboard startup only.
In reality, this is practically unimportant; we don't have enough
dashboard users to persist Shiny sessions very long.
ifelsecoercing dates into numerics; usedplyr::if_elseinstead.