fix: not use negative indices for remove in empty string (#281)

Co-authored-by: Anthony Fu <github@antfu.me>
Rich-Harris · Jul 29, 2024 · 5c1cba0 · 5c1cba0
1 parent d6b2171
commit 5c1cba0
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Showing 3 changed files with 35 additions and 12 deletions.
diff --git 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
@@ -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
@@ -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', () => {