add tests and update doc

DESCRIPTION

@@ -20,7 +20,7 @@ Suggests:
     curl,
     testthat,
     xml2
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.2
 Roxygen: list(markdown = TRUE)
 Language: en-US
 Encoding: UTF-8

NEWS

@@ -1,5 +1,6 @@
-1.9.3
+1.9.4
   - Apply upstream PR https://github.com/github/cmark-gfm/pull/362
+  - Require double-tilde `~~` for the strikethrough extension, for consistency with Pandoc's Markdown
 
 1.9.1
   - Update libcmark-gfm to 0.29.0.gfm.13

R/extensions.R

@@ -6,7 +6,7 @@
 #' Currently the following extensions are supported:
 #'
 #'  - **table** support rendering of tables: [gfm-spec section 4.10](https://github.github.com/gfm/#tables-extension-)
-#'  - **strikethrough** via `~sometext~` syntax: [gfm-spec section 6.5](https://github.github.com/gfm/#strikethrough-extension-)
+#'  - **strikethrough** via `~~sometext~~` syntax: [gfm-spec section 6.5](https://github.github.com/gfm/#strikethrough-extension-)
 #'  - **autolink** automatically turn URLs into hyperlinks: [gfm-spec section 6.9](https://github.github.com/gfm/#autolinks-extension-)
 #'  - **tagfilter** blacklist html tags: `title` `textarea` `style` `xmp` `iframe`
 #' `noembed` `noframes` `script` `plaintext`: [gfm-spec section 6.11](https://github.github.com/gfm/#disallowed-raw-html-extension-)

tests/testthat/test-extensions.R

@@ -47,3 +47,9 @@ test_that("embedded images do not get filtered", {
   expect_equal(md, markdown_html(md))
   expect_equal(md, markdown_commonmark(md))
 })
+
+test_that("strikethrough", {
+  md <- "~Hello~ ~~world~~!"
+  expect_equal(markdown_html(md), "<p>~Hello~ ~~world~~!</p>\n")
+  expect_equal(markdown_html(md, extensions = "strikethrough"), "<p>~Hello~ <del>world</del>!</p>\n")
+})