Fixes #473 by reducing the backtracking to handle the long strings of…

… spaces

index.compiler.spec.tsx

@@ -4824,3 +4824,25 @@ it('#597 handles script tag with empty content', () => {
     </script>
   `)
 })
+
+it('#473 handles content with multiple empty spaces without crashing', () => {
+  render(
+    compiler(
+      '##Long \r\n                                                                                    \r\n ###input \ntest'
+    )
+  )
+
+  expect(root.innerHTML).toMatchInlineSnapshot(`
+    <div>
+      <h2 id="long">
+        Long
+      </h2>
+      <h3 id="input">
+        input
+      </h3>
+      <p>
+        test
+      </p>
+    </div>
+  `)
+})

index.tsx

@@ -185,7 +185,7 @@ const BREAK_LINE_R = /^ {2,}\n/
 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_BLOCK_R = /^(?: {4}[^\n]+\n*)+(?:\n *)*\n?/
 const CODE_INLINE_R = /^(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/
 const CONSECUTIVE_NEWLINE_R = /^(?:\n *)*\n/
 const CR_NEWLINE_R = /\r\n?/g