fix: validate update() range and show indices in range errors (#318)

Author: wahidrizka

src/MagicString.ts

@@ -577,13 +577,17 @@ export default class MagicString {
       while (end < 0) end += this.original.length
     }
 
+    if (start < 0)
+      throw new Error('Character is out of bounds')
     if (end > this.original.length)
       throw new Error('end is out of bounds')
     if (start === end) {
       throw new Error(
         'Cannot overwrite a zero-length range – use appendLeft or prependRight instead',
       )
     }
+    if (start > end)
+      throw new Error(`end must be greater than start (start: ${start}, end: ${end})`)
 
     if (DEBUG)
       this.stats.time('overwrite')
@@ -729,7 +733,7 @@ export default class MagicString {
     if (start < 0 || end > this.original.length)
       throw new Error('Character is out of bounds')
     if (start > end)
-      throw new Error('end must be greater than start')
+      throw new Error(`end must be greater than start (start: ${start}, end: ${end})`)
 
     if (DEBUG)
       this.stats.time('remove')
@@ -770,7 +774,7 @@ export default class MagicString {
     if (start < 0 || end > this.original.length)
       throw new Error('Character is out of bounds')
     if (start > end)
-      throw new Error('end must be greater than start')
+      throw new Error(`end must be greater than start (start: ${start}, end: ${end})`)
 
     if (DEBUG)
       this.stats.time('reset')

test/MagicString.test.ts

@@ -1164,6 +1164,22 @@ describe('magicString', () => {
       assert.throws(() => s.update(0, 1, []), TypeError)
     })
 
+    it('should throw when start is greater than end', () => {
+      const s = new MagicString('problems = 99')
+      assert.throws(() => s.update(9, 5, 'x'), /end must be greater than start \(start: 9, end: 5\)/)
+    })
+
+    it('should report the resolved indices when a negative start lands past end', () => {
+      const s = new MagicString('problems = 99')
+      // -1 resolves to 12, which is past `end`
+      assert.throws(() => s.update(-1, 5, 'x'), /end must be greater than start \(start: 12, end: 5\)/)
+    })
+
+    it('should throw error when using negative indices with empty string', () => {
+      const s = new MagicString('')
+      assert.throws(() => s.update(-2, -1, 'x'), /Character is out of bounds/)
+    })
+
     it('replaces interior inserts with overwrite option', () => {
       const s = new MagicString('abcdefghijkl')
 
@@ -1365,6 +1381,12 @@ describe('magicString', () => {
       const s = new MagicString('')
       assert.throws(() => s.remove(-2, -1), /Character is out of bounds/)
     })
+
+    it('should report the resolved indices when a negative start lands past end', () => {
+      const s = new MagicString('problems = 99')
+      // -1 resolves to 12, which is past `end`
+      assert.throws(() => s.remove(-1, 5), /end must be greater than start \(start: 12, end: 5\)/)
+    })
   })
 
   describe('reset', () => {