From 9332d501ad4862517e66c5b4a13eb0db09b3697a Mon Sep 17 00:00:00 2001
From: Evan Jacobs <x@quantizor.dev>
Date: Mon, 20 Jan 2025 17:01:17 -0500
Subject: [PATCH] refactor: improve inline code performance

---
 .changeset/plenty-dodos-collect.md         |  5 +++++
 .prettierignore                            |  1 +
 __snapshots__/index.compiler.spec.tsx.snap |  6 +++---
 fixture.md                                 |  2 +-
 index.tsx                                  | 15 ++++++++++-----
 5 files changed, 20 insertions(+), 9 deletions(-)
 create mode 100644 .changeset/plenty-dodos-collect.md
 create mode 100644 .prettierignore

diff --git a/.changeset/plenty-dodos-collect.md b/.changeset/plenty-dodos-collect.md
new file mode 100644
index 00000000..2ab20106
--- /dev/null
+++ b/.changeset/plenty-dodos-collect.md
@@ -0,0 +1,5 @@
+---
+'markdown-to-jsx': patch
+---
+
+Rework inline code syntax handling, handle escaped characters in code blocks correctly so they render without the backslash.
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 00000000..0aed9848
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1 @@
+fixture.md
diff --git a/__snapshots__/index.compiler.spec.tsx.snap b/__snapshots__/index.compiler.spec.tsx.snap
index ceabbfa8..1ca360b3 100644
--- a/__snapshots__/index.compiler.spec.tsx.snap
+++ b/__snapshots__/index.compiler.spec.tsx.snap
@@ -924,7 +924,7 @@ line. To avoid this, you can backslash-escape the period:
   </p>
   <pre>
     <code>
-      1986\\. What a great season.
+      1986. What a great season.
     </code>
   </pre>
   <h3 id="precode">
@@ -1433,7 +1433,7 @@ escape it:
   </p>
   <pre>
     <code>
-      \\*this text is surrounded by literal asterisks\\*
+      *this text is surrounded by literal asterisks*
     </code>
   </pre>
   <h3 id="code">
@@ -1688,7 +1688,7 @@ backslashes before the asterisks, like this:
   </p>
   <pre>
     <code>
-      \\*literal asterisks\\*
+      *literal asterisks*
     </code>
   </pre>
   <p>
diff --git a/fixture.md b/fixture.md
index 9434ec56..ee056899 100644
--- a/fixture.md
+++ b/fixture.md
@@ -745,7 +745,7 @@ escape it:
 
 <h3 id="code">Code</h3>
 
-To indicate a span of code, wrap it with backtick quotes (`` ` ``).
+To indicate a span of code, wrap it with backtick quotes (`\``).
 Unlike a pre-formatted code block, a code span indicates code within a
 normal paragraph. For example:
 
diff --git a/index.tsx b/index.tsx
index bc1c579b..5f4ea85b 100644
--- a/index.tsx
+++ b/index.tsx
@@ -190,7 +190,7 @@ const BREAK_THEMATIC_R = /^(?:( *[-*_])){3,} *(?:\n *)+\n/
 const CODE_BLOCK_FENCED_R =
   /^(?: {1,3})?(`{3,}|~{3,}) *(\S+)? *([^\n]*?)?\n([\s\S]*?)(?:\1\n?|$)/
 const CODE_BLOCK_R = /^(?: {4}[^\n]+\n*)+(?:\n *)+\n?/
-const CODE_INLINE_R = /^(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/
+const CODE_INLINE_R = /^(`+)((?:\\`|[^`])+)\1/
 const CONSECUTIVE_NEWLINE_R = /^(?:\n *)*\n/
 const CR_NEWLINE_R = /\r\n?/g
 
@@ -320,6 +320,7 @@ const TEXT_MARKED_R = new RegExp(`^==${INLINE_SKIP_R}==`)
 const TEXT_STRIKETHROUGHED_R = new RegExp(`^~~${INLINE_SKIP_R}~~`)
 
 const TEXT_ESCAPED_R = /^\\([^0-9A-Za-z\s])/
+const TEXT_UNESCAPE_R = /\\([^0-9A-Za-z\s])/g
 
 /**
  * Always take the first character, then eagerly take text until a double space
@@ -460,6 +461,7 @@ function generateListRule(
         .match(LIST_ITEM_R)
 
       let lastItemWasAParagraph = false
+
       const itemContent = items.map(function (item, i) {
         // We need to see how far indented the item is:
         const space = LIST_ITEM_PREFIX_R.exec(item)[0].length
@@ -495,7 +497,7 @@ function generateListRule(
           containsBlocks || (isLastItem && lastItemWasAParagraph)
         lastItemWasAParagraph = thisItemIsAParagraph
 
-        // backup our state for restoration afterwards. We're going to
+        // backup our state for delta afterwards. We're going to
         // want to set state.list to true, and state.inline depending
         // on our list's looseness.
         const oldStateInline = state.inline
@@ -1400,7 +1402,10 @@ export function compiler(
       parse(capture /*, parse, state*/) {
         return {
           lang: undefined,
-          text: capture[0].replace(/^ {4}/gm, '').replace(/\n+$/, ''),
+          text: capture[0]
+            .replace(/^ {4}/gm, '')
+            .replace(/\n+$/, '')
+            .replaceAll(TEXT_UNESCAPE_R, '$1'),
         }
       },
 
@@ -1430,7 +1435,7 @@ export function compiler(
           // if capture[3] it's additional metadata
           attrs: attrStringToMap('code', capture[3] || ''),
           lang: capture[2] || undefined,
-          text: capture[4],
+          text: capture[4].replaceAll(TEXT_UNESCAPE_R, '$1'),
           type: RuleType.codeBlock,
         }
       },
@@ -1441,7 +1446,7 @@ export function compiler(
       order: Priority.LOW,
       parse(capture /*, parse, state*/) {
         return {
-          text: capture[2],
+          text: capture[2].replaceAll(TEXT_UNESCAPE_R, '$1'),
         }
       },
       render(node, output, state) {