From 5c1cba04ed1a45374ab17b07fc335951d59c1a61 Mon Sep 17 00:00:00 2001
From: Wang Wenzhe <mysteryven@gmail.com>
Date: Mon, 29 Jul 2024 20:33:18 +0800
Subject: [PATCH] fix: not use negative indices for remove in empty string
 (#281)

Co-authored-by: Anthony Fu <github@antfu.me>
---
 benchmark/data.js   | 10 ++++++----
 src/MagicString.js  | 24 ++++++++++++++++--------
 test/MagicString.js | 13 +++++++++++++
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/benchmark/data.js b/benchmark/data.js
index f48c363..ffc840b 100644
--- a/benchmark/data.js
+++ b/benchmark/data.js
@@ -663,10 +663,12 @@ class MagicString {
     return this.intro + lineStr;
   }
   slice(start = 0, end = this.original.length) {
-    while (start < 0)
-      start += this.original.length;
-    while (end < 0)
-      end += this.original.length;
+    if (this.original.length !== 0) {
+      while (start < 0)
+        start += this.original.length;
+      while (end < 0)
+        end += this.original.length;
+    }
     let result = "";
     let chunk = this.firstChunk;
     while (chunk && (chunk.start > start || chunk.end <= start)) {
diff --git a/src/MagicString.js b/src/MagicString.js
index 49c05cf..7e37e49 100644
--- a/src/MagicString.js
+++ b/src/MagicString.js
@@ -360,8 +360,10 @@ export default class MagicString {
 	update(start, end, content, options) {
 		if (typeof content !== 'string') throw new TypeError('replacement content must be a string');
 
-		while (start < 0) start += this.original.length;
-		while (end < 0) end += this.original.length;
+		if (this.original.length !== 0) {
+			while (start < 0) start += this.original.length;
+			while (end < 0) end += this.original.length;
+		}
 
 		if (end > this.original.length) throw new Error('end is out of bounds');
 		if (start === end)
@@ -469,8 +471,10 @@ export default class MagicString {
 	}
 
 	remove(start, end) {
-		while (start < 0) start += this.original.length;
-		while (end < 0) end += this.original.length;
+		if (this.original.length !== 0) {
+			while (start < 0) start += this.original.length;
+			while (end < 0) end += this.original.length;
+		}
 
 		if (start === end) return this;
 
@@ -497,8 +501,10 @@ export default class MagicString {
 	}
 
 	reset(start, end) {
-		while (start < 0) start += this.original.length;
-		while (end < 0) end += this.original.length;
+		if (this.original.length !== 0) {
+			while (start < 0) start += this.original.length;
+			while (end < 0) end += this.original.length;
+		}
 
 		if (start === end) return this;
 
@@ -564,8 +570,10 @@ export default class MagicString {
 	}
 
 	slice(start = 0, end = this.original.length) {
-		while (start < 0) start += this.original.length;
-		while (end < 0) end += this.original.length;
+		if (this.original.length !== 0) {
+			while (start < 0) start += this.original.length;
+			while (end < 0) end += this.original.length;
+		}
 
 		let result = '';
 
diff --git a/test/MagicString.js b/test/MagicString.js
index a7d881a..90bce48 100644
--- a/test/MagicString.js
+++ b/test/MagicString.js
@@ -1234,6 +1234,19 @@ describe('MagicString', () => {
 
 			assert.equal(s.toString(), 'abchidejkl');
 		});
+
+		it('should accept negative indices', () => {
+			const s = new MagicString('abcde');
+			// "abcde"
+			//     ^
+			s.remove(-2, -1);
+			assert.equal(s.toString(), 'abce');
+		});
+
+		it('should throw error when using negative indices with empty string', () => {
+			const s = new MagicString('');
+			assert.throws(() => s.remove(-2, -1), /Error: Character is out of bounds/);
+		});
 	});
 
 	describe('reset', () => {