Dash for R does not currently support adding meta tags #141
Description
Dash for Python has supported meta tags since plotly/dash#286, and Dash for R should support them as well.
The initial plan was to bundle this feature in with "index customization" (which is the last of the parity features to implement now that hot reloading support is available), but it's a priority and it should be tackled first.
The implementation will mirror that in Dash for Python: an optional meta_tags argument which accepts a list-of-lists structure to control the name and content fields when initializing the Dash app object. In R, the syntax will likely resemble
metas <- list(
list(name = 'description',
content = 'My description')
)
app <- Dash$new(meta_tags=metas)