From bbc02f6a4798c9f352a6afda47657fb952e1f10d Mon Sep 17 00:00:00 2001
From: gka <gka@users.noreply.github.com>
Date: Mon, 14 Nov 2022 21:02:06 +0100
Subject: [PATCH] feat: escape special markdown characters

---
 src/index.js  | 13 ++++++++++++-
 test/index.js | 17 +++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/index.js b/src/index.js
index 3938c5c..ab24df9 100644
--- a/src/index.js
+++ b/src/index.js
@@ -30,6 +30,8 @@ export default function parse(md, prevLinks) {
 		links = prevLinks || {},
 		last = 0,
 		chunk, prev, token, inner, t;
+	// escape special characters
+	md = md.replace(/\\([*_[\]{}`<>()#+\-!|.])/g, m => `&%${m.charCodeAt(1)}%;`);
 
 	function tag(token) {
 		let desc = TAGS[token[1] || ''];
@@ -105,5 +107,14 @@ export default function parse(md, prevLinks) {
 		out += chunk;
 	}
 
-	return (out + md.substring(last) + flush()).replace(/^\n+|\n+$/g, '');
+	return (
+		out +
+		md
+			.substring(last)
+			// unscape special characters
+			.replace(/&%[0-9]+%;/g, (m) =>
+				String.fromCharCode(+m.substring(2, m.length - 2))
+			) +
+		flush()
+	).replace(/^\n+|\n+$/g, '');
 }
diff --git a/test/index.js b/test/index.js
index 5262b16..8fcac77 100644
--- a/test/index.js
+++ b/test/index.js
@@ -167,4 +167,21 @@ describe('snarkdown()', () => {
 			expect(snarkdown('`')).to.equal('`');
 		});
 	});
+
+	describe('escaping', () => {
+		it('should escape special charcters', () => {
+			expect(snarkdown('\\*foo')).to.equal('*foo');
+			expect(snarkdown('this\\*is\\*important')).to.equal('this*is*important');
+			expect(snarkdown('\\_foo')).to.equal('_foo');
+			expect(snarkdown('\\[foo')).to.equal('[foo');
+			expect(snarkdown('\\]foo')).to.equal(']foo');
+			expect(snarkdown('\\(foo')).to.equal('(foo');
+			expect(snarkdown('\\)foo')).to.equal(')foo');
+			expect(snarkdown('\\{foo')).to.equal('{foo');
+			expect(snarkdown('\\}foo')).to.equal('}foo');
+			expect(snarkdown('\\-foo')).to.equal('-foo');
+			expect(snarkdown('\\+foo')).to.equal('+foo');
+			expect(snarkdown('\\#foo')).to.equal('#foo');
+		});
+	});
 });