From dfba2bc34fffa748b9a00d974dbcd08fce76ee4c Mon Sep 17 00:00:00 2001
From: Nate Moore <nate@natemoo.re>
Date: Fri, 27 Sep 2024 08:45:16 -0500
Subject: [PATCH] fix: update attr balancing logic

---
 src/index.ts       | 15 ++++++++-----
 test/astro.test.ts | 55 +++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 80e2ed1..72935a0 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -233,14 +233,19 @@ export function parse(input: string | ReturnType<typeof html>): any {
 			} else {
 				// Ensure attr expressions are balanced
 				if (!isBalanced(token[3])) {
-					token[3] += '>'
-					let infiniteloop = 0;
+					const max = token[3].length + str.slice(DOM_PARSER_RE.lastIndex).length;
 					while (!isBalanced(token[3])) {
-						if (infiniteloop === 999) throw new Error('Infinite loop detected!');
-						const chunk = str.substring(DOM_PARSER_RE.lastIndex, DOM_PARSER_RE.lastIndex + str.substring(DOM_PARSER_RE.lastIndex).indexOf('>'));
+						if (token[3].length > max) {
+							// TODO: better error stacktrace
+							throw new Error(`Syntax error!\n${token[3]}`);
+						}
+						const gtIndex = str.substring(DOM_PARSER_RE.lastIndex).indexOf('>');
+						if (gtIndex != -1) {
+							token[3] += '>'
+						}
+						const chunk = str.substring(DOM_PARSER_RE.lastIndex, DOM_PARSER_RE.lastIndex + gtIndex);
 						token[3] += chunk;
 						DOM_PARSER_RE.lastIndex += chunk.length + 1;
-						infiniteloop++;
 					}
 				}
 				tag = {
diff --git a/test/astro.test.ts b/test/astro.test.ts
index 7a179da..7296a9a 100644
--- a/test/astro.test.ts
+++ b/test/astro.test.ts
@@ -17,19 +17,64 @@ let value: string;
     expect(output).toEqual(input);
   });
 
-    it("does not hang on unmatched braces", async () => {
+  it("handles invalid expressions", async () => {
     const input = `---
-let value: string;
+let value = { awesome: { }};
 ---
 
-<h1>Hello {world}</h1>
+<h1>Hello {world!}</h1>
 <Component a="1" b="2" c={\`three\`} items={astro.map((item: string) => {
-  const value: string = item.split('{').reverse().join('{');
+  const value: string = item.split('').reverse().join('');
   return value;
 })}>Hello world</Component>`;
     const doc = parse(input);
     const output = await render(doc);
     expect(output).toEqual(input);
   });
-});
 
+   it("gracefully handles elements inside attributes", async () => {
+    const input = `---
+let value: string;
+---
+
+<h1>Hello {world}</h1>
+<Component a="1" b="2" c={\`three\`} items={astro.map((item: string) => <li>{item}</li>)}>Hello world</Component>`;
+    const doc = parse(input);
+    expect(doc.children.at(-1).attributes.items).toEqual('{astro.map((item: string) => <li>{item}</li>)}');
+    const output = await render(doc);
+    expect(output).toEqual(input);
+  });
+
+  it("fails with error on unmatched braces", async () => {
+    const input = `
+<Component items={astro.map(({item: string) => <li>{item}</li>)}>Hello world</Component>`;
+    let error: unknown;
+    try {
+      parse(input);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeInstanceOf(Error);
+  });
+
+  it("handles single-line comments", async () => {
+    const input = '<Component items={astro.map((item: string) => <li>\n//{{{((([[[[{item}\n</li>)}>Hello world</Component>';
+    const doc = parse(input);
+    const output = await render(doc);
+    expect(output).toEqual(input);
+  });
+
+  it("handles multi-line comments", async () => {
+    const input = '<Component items={astro.map((item: string) => <li>\n/* \n * {{{ }\n */\n{item}</li>)}>Hello world</Component>';
+    const doc = parse(input);
+    const output = await render(doc);
+    expect(output).toEqual(input);
+  });
+
+  it("handles regex", async () => {
+    const input = '<Component items={astro.map((item: string) => <li>\n{/{{{{/gmi.test(item)}\n</li>)}>Hello world</Component>';
+    const doc = parse(input);
+    const output = await render(doc);
+    expect(output).toEqual(input);
+  });
+});