From 403a4bb911c8c36a1c7b7c605f57e3e8679e9532 Mon Sep 17 00:00:00 2001
From: atomiks <cc.glows@gmail.com>
Date: Fri, 8 Dec 2023 18:53:16 +1100
Subject: [PATCH] fix: prevent loop with overlapping chars (#130)

---
 src/chars/charsHighlighter.ts          | 23 ++++-----
 src/chars/getElementsToHighlight.ts    |  3 +-
 src/index.ts                           |  3 +-
 src/utils.ts                           |  9 +---
 test/fixtures/highlightedCharsLoop.md  |  8 ++++
 test/results/highlightedCharsLoop.html | 64 ++++++++++++++++++++++++++
 6 files changed, 83 insertions(+), 27 deletions(-)
 create mode 100644 test/fixtures/highlightedCharsLoop.md
 create mode 100644 test/results/highlightedCharsLoop.html

diff --git a/src/chars/charsHighlighter.ts b/src/chars/charsHighlighter.ts
index 7c01f24..019db48 100644
--- a/src/chars/charsHighlighter.ts
+++ b/src/chars/charsHighlighter.ts
@@ -4,7 +4,7 @@ import type { CharsElement } from '../..';
 import { getElementsToHighlight } from './getElementsToHighlight';
 import { wrapHighlightedChars } from './wrapHighlightedChars';
 import { toString } from 'hast-util-to-string';
-import { hasOwnProperty, isElement } from '../utils';
+import { isElement } from '../utils';
 
 /**
  * Loops through the child nodes and finds the nodes that make up the chars.
@@ -73,7 +73,7 @@ export function charsHighlighter(
             const props = isElement(childNode) ? childNode.properties : {};
             if (
               props &&
-              !hasOwnProperty(props, 'rehype-pretty-code-visited') &&
+              !Object.hasOwn(props, 'rehype-pretty-code-visited') &&
               !Object.hasOwn(props, 'data-highlighted-chars-mark')
             ) {
               return toString(childNode);
@@ -82,19 +82,12 @@ export function charsHighlighter(
           .join('');
       }
     }
+  });
 
-    element.children.forEach((childNode) => {
-      if (!isElement(childNode)) {
-        return;
-      }
-
-      if (
-        hasOwnProperty(childNode.properties ?? {}, 'rehype-pretty-code-visited')
-      ) {
-        if (childNode.properties) {
-          delete childNode.properties['rehype-pretty-code-visited'];
-        }
-      }
-    });
+  element.children.forEach((childNode) => {
+    if (!isElement(childNode)) return;
+    if (Object.hasOwn(childNode.properties, 'rehype-pretty-code-visited')) {
+      delete childNode.properties['rehype-pretty-code-visited'];
+    }
   });
 }
diff --git a/src/chars/getElementsToHighlight.ts b/src/chars/getElementsToHighlight.ts
index 0856d41..6ca6e01 100644
--- a/src/chars/getElementsToHighlight.ts
+++ b/src/chars/getElementsToHighlight.ts
@@ -5,7 +5,6 @@ import {
   getContent,
   nextElementMaybeContinuesChars,
 } from './utils';
-import { hasOwnProperty } from '../utils';
 
 export function getElementsToHighlight(
   element: Element,
@@ -32,7 +31,7 @@ export function getElementsToHighlight(
         !maybeElement ||
         maybeElement.type !== 'element' ||
         // ignore any previously matched chars within
-        hasOwnProperty(
+        Object.hasOwn(
           maybeElement.properties ?? {},
           'rehype-pretty-code-visited',
         )
diff --git a/src/index.ts b/src/index.ts
index 91ad984..adcf4fb 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -20,7 +20,6 @@ import {
   isInlineCode,
   getThemeNames,
   replaceLineClass,
-  hasOwnProperty,
 } from './utils';
 
 interface ApplyProps {
@@ -111,7 +110,7 @@ function apply(
         }
       }
 
-      if (hasOwnProperty(code.properties, 'data-line-numbers')) {
+      if (Object.hasOwn(code.properties, 'data-line-numbers')) {
         code.properties['data-line-numbers-max-digits'] =
           lineNumbersMaxDigits.toString().length;
       }
diff --git a/src/utils.ts b/src/utils.ts
index 4a67063..4fc2fe6 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -4,7 +4,7 @@ import type { Theme } from '..';
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export function isJSONTheme(value: any): value is ThemeRegistrationRaw {
-  return value ? hasOwnProperty(value, 'tokenColors') : false;
+  return value ? Object.hasOwn(value, 'tokenColors') : false;
 }
 
 export function isElement(
@@ -17,13 +17,6 @@ export function isText(value: ElementContent | null): value is Text {
   return value ? value.type === 'text' : false;
 }
 
-export function hasOwnProperty(
-  object: Record<string, unknown>,
-  string: string,
-) {
-  return {}.hasOwnProperty.call(object, string);
-}
-
 export function isInlineCode(
   element: Element,
   parent: Element | Root | undefined,
diff --git a/test/fixtures/highlightedCharsLoop.md b/test/fixtures/highlightedCharsLoop.md
new file mode 100644
index 0000000..604283c
--- /dev/null
+++ b/test/fixtures/highlightedCharsLoop.md
@@ -0,0 +1,8 @@
+# Highlighted chars loop
+
+Overlapping chars should not cause infinite loop
+
+```js /carrot/ /car/
+const carrot = 'carrot';
+const car = 'car';
+```
diff --git a/test/results/highlightedCharsLoop.html b/test/results/highlightedCharsLoop.html
new file mode 100644
index 0000000..826f2a0
--- /dev/null
+++ b/test/results/highlightedCharsLoop.html
@@ -0,0 +1,64 @@
+
+<style>
+  html {
+    font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif;
+  }
+  body {
+    margin: 30px auto;
+    max-width: 800px;
+  }
+  pre {
+    padding: 16px;
+  }
+  span > code {
+    background: black;
+    padding: 4px;
+  }
+  [data-highlighted-line], [data-highlighted-chars] {
+    background-color: rgba(255, 255, 255, 0.25);
+  }
+  code[data-line-numbers] {
+    counter-reset: line;
+  }
+  code[data-line-numbers]>[data-line]::before {
+    counter-increment: line;
+    content: counter(line);
+    display: inline-block;
+    width: 1rem;
+    margin-right: 2rem;
+    text-align: right;
+    color: gray;
+  }
+
+  [data-rehype-pretty-code-figure] code[data-theme*=' '],
+  [data-rehype-pretty-code-figure] code[data-theme*=' '] span {
+    color: var(--shiki-light) !important;
+    background-color: var(--shiki-light-bg) !important;
+  }
+
+  @media (prefers-color-scheme: dark) {
+    [data-rehype-pretty-code-figure] code[data-theme*=' '],
+    [data-rehype-pretty-code-figure] code[data-theme*=' '] span {
+      color: var(--shiki-dark) !important;
+      background-color: var(--shiki-dark-bg) !important;
+    }
+  }
+
+  .diff.add {
+    background-color: rgba(0, 255, 100, 0.25);
+  }
+  .diff.remove {
+    background-color: rgba(255, 100, 200, 0.35);
+  }
+</style>
+<h1>Highlighted chars loop</h1>
+<p>Overlapping chars should not cause infinite loop</p>
+<figure data-rehype-pretty-code-figure="">
+  <pre
+    style="background-color: #24292e; color: #e1e4e8"
+    tabindex="0"
+    data-language="js"
+    data-theme="github-dark"
+  ><code data-language="js" data-theme="github-dark" style="display: grid;"><span data-line=""><span style="color:#F97583">const</span><span style="color:#79B8FF"> </span><mark data-highlighted-chars="" class="word"><span style="color:#79B8FF">carrot</span></mark><span style="color:#F97583"> =</span><span style="color:#9ECBFF"> '</span><mark data-highlighted-chars="" class="word"><span style="color:#9ECBFF">carrot</span></mark><span style="color:#9ECBFF">'</span><span style="color:#E1E4E8">;</span></span>
+<span data-line=""><span style="color:#F97583">const</span><span style="color:#79B8FF"> </span><mark data-highlighted-chars="" class="word"><span style="color:#79B8FF">car</span></mark><span style="color:#F97583"> =</span><span style="color:#9ECBFF"> '</span><mark data-highlighted-chars="" class="word"><span style="color:#9ECBFF">car</span></mark><span style="color:#9ECBFF">'</span><span style="color:#E1E4E8">;</span></span></code></pre>
+</figure>