Documentation improvements for v1.6 (rstudio#3255)

NEWS.md

@@ -2,6 +2,20 @@
 shiny 1.6.0
 ================
 
+This release focuses on improvements in three main areas:
+
+1. Better theming (and Bootstrap 4) support:
+  * The `theme` argument of `fluidPage()`, `navbarPage()`, and `bootstrapPage()` all now understand `bslib::bs_theme()` objects, which can be used to opt-into Bootstrap 4, use any Bootswatch theme, and/or implement custom themes without writing any CSS. 
+  * The `session` object now includes `$setCurrentTheme()` and `$getCurrentTheme()` methods to dynamically update (or obtain) the page's `theme` after initial load, which is useful for things such as [adding a dark mode switch to an app](https://rstudio.github.io/bslib/articles/theming.html#dynamic-theming-in-shiny) or some other "real-time" theming tool like `bslib::bs_themer()`.
+  * For more details, see [`{bslib}`'s website](https://rstudio.github.io/bslib)
+
+2. Caching of `reactive()` and `render*()` (e.g. `renderText()`, `renderTable()`, etc) expressions.
+  * Such expressions automatically cache their _most recent value_, which helps to avoid redundant computation within a single "flush" of reactivity. The new `bindCache()` function can be used to cache _all previous values_ (as long as they fit in the cache). This cache may be optionally scoped within and/or across user sessions, possibly leading to huge performance gains, especially when deployed at scale across user sessions.
+  * For more details, see `help(bindCache, package = "shiny")`
+
+3. Various improvements to accessibility for screen-reader and keyboard users.
+  * For more details, see the accessibility section below.
+
 ## Full changelog
 
 ### Breaking changes

R/shiny.R

@@ -193,6 +193,14 @@ workerId <- local({
 #'   An environment for app authors and module/package authors to store whatever
 #'   session-specific data they want.
 #' }
+#' \item{user}{
+#'   User's log-in information. Useful for identifying users on hosted platforms
+#'   such as RStudio Connect and Shiny Server.
+#' }
+#' \item{groups}{
+#'   The `user`'s relevant group information. Useful for determining what
+#'   privileges the user should or shouldn't have.
+#' }
 #' \item{resetBrush(brushId)}{
 #'   Resets/clears the brush with the given `brushId`, if it exists on
 #'   any `imageOutput` or `plotOutput` in the app.

README.md

@@ -7,50 +7,51 @@
 
 <!-- badges: end -->
 
-Shiny is a new package from RStudio that makes it incredibly easy to build interactive web applications with R.
-
-For an introduction and examples, visit the [Shiny Dev Center](https://shiny.rstudio.com/).
-
-If you have general questions about using Shiny, please use the [RStudio Community website](https://community.rstudio.com). For bug reports, please use the [issue tracker](https://github.com/rstudio/shiny/issues).
+Easily build rich and productive interactive web apps in R &mdash; no HTML/CSS/JavaScript required.
 
 ## Features
 
-* Build useful web applications with only a few lines of code&mdash;no JavaScript required.
-* Shiny applications are automatically "live" in the same way that spreadsheets are live. Outputs change instantly as users modify inputs, without requiring a reload of the browser.
-* Shiny user interfaces can be built entirely using R, or can be written directly in HTML, CSS, and JavaScript for more flexibility.
-* Works in any R environment (Console R, Rgui for Windows or Mac, ESS, StatET, RStudio, etc.).
-* Attractive default UI theme based on [Bootstrap](https://getbootstrap.com/).
-* A highly customizable slider widget with built-in support for animation.
-* Prebuilt output widgets for displaying plots, tables, and printed output of R objects.
-* Fast bidirectional communication between the web browser and R using the [httpuv](https://github.com/rstudio/httpuv) package.
-* Uses a [reactive](https://en.wikipedia.org/wiki/Reactive_programming) programming model that eliminates messy event handling code, so you can focus on the code that really matters.
-* Develop and redistribute your own Shiny widgets that other developers can easily drop into their own applications (coming soon!).
+* An intuitive and extensible [reactive programming](https://en.wikipedia.org/wiki/Reactive_programming) model which makes it easy to transform existing R code into a "live app" where outputs automatically react to new user input.
+  * Compared to event-based programming, reactivity allows Shiny to do the minimum amount of work when input(s) change, and allows humans to more easily reason about complex [MVC logic](https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller).
+* A prebuilt set of highly sophisticated, customizable, and easy-to-use widgets (e.g., plots, tables, sliders, dropdowns, date pickers, and more).
+* An attractive default look based on [Bootstrap](https://getbootstrap.com/) which can also be easily customized with the [bslib](https://github.com/rstudio/bslib) package or avoided entirely with more direct R bindings to HTML/CSS/JavaScript.
+* Seamless integration with [R Markdown](https://shiny.rstudio.com/articles/interactive-docs.html), making it easy to embed numerous applications natively within a larger dynamic document.
+* Tools for improving and monitoring performance, including native support for [async programming](https://blog.rstudio.com/2018/06/26/shiny-1-1-0/), [caching](https://talks.cpsievert.me/20201117), [load testing](https://rstudio.github.io/shinyloadtest/), and [more](https://support.rstudio.com/hc/en-us/articles/231874748-Scaling-and-Performance-Tuning-in-RStudio-Connect).
+* [Modules](https://shiny.rstudio.com/articles/modules.html): a framework for reducing code duplication and complexity.
+* An ability to [bookmark application state](https://shiny.rstudio.com/articles/bookmarking-state.html) and/or [generate code to reproduce output(s)](https://github.com/rstudio/shinymeta).
+* A rich ecosystem of extension packages for more [custom widgets](http://www.htmlwidgets.org/), [input validation](https://github.com/rstudio/shinyvalidate), [unit testing](https://github.com/rstudio/shinytest), and more.
 
 ## Installation
 
-To install the stable version from CRAN, simply run the following from an R console:
+To install the stable version from CRAN:
 
 ```r
 install.packages("shiny")
 ```
 
-To install the latest development builds directly from GitHub, run this instead:
+## Getting Started
+
+Once installed, load the library and run an example:
 
 ```r
-if (!require("remotes"))
-  install.packages("remotes")
-remotes::install_github("rstudio/shiny")
+library(shiny)
+# Launches an app, with the app's source code included
+runExample("06_tabsets")
+# Lists more prepackaged examples
+runExample()
 ```
 
-## Getting Started
+For more examples and inspiration, check out the [Shiny User Gallery](https://shiny.rstudio.com/gallery/).
+
+For help with learning fundamental Shiny programming concepts, check out the [Mastering Shiny](https://mastering-shiny.org/) book and the [Shiny Tutorial](https://shiny.rstudio.com/tutorial/). The former is currently more up-to-date with modern Shiny features, whereas the latter takes a deeper, more visual, dive into fundamental concepts.
 
-To learn more we highly recommend you check out the [Shiny Tutorial](https://shiny.rstudio.com/tutorial/). The tutorial explains the framework in-depth, walks you through building a simple application, and includes extensive annotated examples.
+## Getting Help
 
-## Development notes
+To ask a question about Shiny, please use the [RStudio Community website](https://community.rstudio.com/new-topic?category=shiny&tags=shiny). 
 
-The Javascript code in Shiny is minified using tools that run on Node.js. See the tools/ directory for more information.
+For bug reports, please use the [issue tracker](https://github.com/rstudio/shiny/issues) and also keep in mind that by [writing a good bug report](https://github.com/rstudio/shiny/wiki/Writing-Good-Bug-Reports), you're more likely to get help with your problem. 
 
-## Guidelines for contributing
+## Contributing
 
 We welcome contributions to the **shiny** package. Please see our [CONTRIBUTING.md](https://github.com/rstudio/shiny/blob/master/.github/CONTRIBUTING.md) file for detailed guidelines of how to contribute.