Merge pull request #21 from jburianek/fix-escaping

Fix escaping for Slack

src/index.ts

@@ -24,7 +24,29 @@ export async function markdownToBlocks(
   body: string,
   options: ParsingOptions = {}
 ): Promise<KnownBlock[]> {
-  const tokens = marked.lexer(body);
+  // Slack only wants &, <, and > escaped
+  // https://api.slack.com/reference/surfaces/formatting#escaping
+  const replacements: Record<string, string> = {
+    '&': '&amp;',
+    '<': '&lt;',
+    '>': '&gt;',
+  };
+
+  const lexer = new marked.Lexer();
+  lexer.options.tokenizer = new marked.Tokenizer();
+  lexer.options.tokenizer.inlineText = src => {
+    const text = src.replace(/[&<>]/g, char => {
+      return replacements[char];
+    });
+
+    return {
+      type: 'text',
+      raw: src,
+      text: text,
+    };
+  };
+
+  const tokens = lexer.lex(body);
 
   return parseBlocks(tokens, options);
 }

test/integration.spec.ts

@@ -126,4 +126,10 @@ if (a === 'hi') {
       expect(actual).toStrictEqual(expected);
     });
   });
+
+  it('should correctly escape text', async () => {
+    const actual = await markdownToBlocks('<>&\'""\'&><');
+    const expected = [slack.section('&lt;&gt;&amp;\'""\'&amp;&gt;&lt;')];
+    expect(actual).toStrictEqual(expected);
+  });
 });