From f647aa7346eba0f0b9be33ff2a792fcbeac46c30 Mon Sep 17 00:00:00 2001
From: nteetor <nate@haufin.ch>
Date: Thu, 26 Nov 2020 10:23:14 -0600
Subject: [PATCH] feat(visible): small utility function for visibility

---
 DESCRIPTION                   |  1 +
 NAMESPACE                     |  1 +
 R/visible.R                   | 34 ++++++++++++++++++++++++++++++++++
 man/visible.Rd                | 27 +++++++++++++++++++++++++++
 tests/testthat/test-visible.R | 11 +++++++++++
 5 files changed, 74 insertions(+)
 create mode 100644 R/visible.R
 create mode 100644 man/visible.Rd
 create mode 100644 tests/testthat/test-visible.R

diff --git a/DESCRIPTION b/DESCRIPTION
index 35b9c16..4bb3bff 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -54,5 +54,6 @@ Collate:
     'shadow.R'
     'text.R'
     'utils-docs.R'
+    'visible.R'
     'width.R'
     'zzz.R'
diff --git a/NAMESPACE b/NAMESPACE
index 7cc36a0..4b964a3 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -22,6 +22,7 @@ export(padding)
 export(position)
 export(shadow)
 export(text)
+export(visible)
 export(width)
 export(with_style)
 import(rlang)
diff --git a/R/visible.R b/R/visible.R
new file mode 100644
index 0000000..013b29b
--- /dev/null
+++ b/R/visible.R
@@ -0,0 +1,34 @@
+visible_value <- function(value) {
+  if (is_true(value)) {
+    "visible"
+  } else if (is_false(value)) {
+    "invisible"
+  }
+}
+
+#' Element visibility
+#'
+#' The `visible()` function changes the visibility of a tag element. An
+#' invisible element is both visually hidden and is also hidden from screen
+#' readers.
+#'
+#' @inheritParams background
+#'
+#' @param value One of `TRUE` or `FALSE` specifying if the element is visible,
+#'   defaults to `TRUE`.
+#'
+#' @export
+#' @examples
+#'
+#' library(htmltools)
+#'
+#' div("I am hidden") %>%
+#'   visible(FALSE)
+#'
+visible <- function(x, value) {
+  assert_subject(x)
+
+  class <- visible_value(value)
+
+  add_class(x, class)
+}
diff --git a/man/visible.Rd b/man/visible.Rd
new file mode 100644
index 0000000..3b69e8d
--- /dev/null
+++ b/man/visible.Rd
@@ -0,0 +1,27 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/visible.R
+\name{visible}
+\alias{visible}
+\title{Element visibility}
+\usage{
+visible(x, value)
+}
+\arguments{
+\item{x}{A tag element or \link{.style} pronoun.}
+
+\item{value}{One of \code{TRUE} or \code{FALSE} specifying if the element is visible,
+defaults to \code{TRUE}.}
+}
+\description{
+The \code{visible()} function changes the visibility of a tag element. An
+invisible element is both visually hidden and is also hidden from screen
+readers.
+}
+\examples{
+
+library(htmltools)
+
+div("I am hidden") \%>\%
+  visible(FALSE)
+
+}
diff --git a/tests/testthat/test-visible.R b/tests/testthat/test-visible.R
new file mode 100644
index 0000000..cf73a6e
--- /dev/null
+++ b/tests/testthat/test-visible.R
@@ -0,0 +1,11 @@
+context("visible()")
+
+test_that("adds classes", {
+  div() %>%
+    visible(FALSE) %>%
+    expect_html_class("invisible")
+
+  div() %>%
+    visible(TRUE) %>%
+    expect_html_class("visible")
+})