refactor: use specific error types in decoders and parser

src/decoders.ts

@@ -29,7 +29,7 @@ import {
 export function decodeValueFromLines(cursor: LineCursor, options: ResolvedDecodeOptions): JsonValue {
   const first = cursor.peek()
   if (!first) {
-    throw new Error('No content to decode')
+    throw new ReferenceError('No content to decode')
   }
 
   // Check for root array
@@ -230,7 +230,7 @@ function decodeListArray(
   if (options.strict && !cursor.atEnd()) {
     const nextLine = cursor.peek()
     if (nextLine && nextLine.depth === itemDepth && nextLine.content.startsWith(LIST_ITEM_PREFIX)) {
-      throw new Error(`Expected ${header.length} list array items, but found more`)
+      throw new RangeError(`Expected ${header.length} list array items, but found more`)
     }
   }
 
@@ -284,7 +284,7 @@ function decodeTabularArray(
 
       if (!hasColon) {
         // No colon = data row (for single-field tables)
-        throw new Error(`Expected ${header.length} tabular rows, but found more`)
+        throw new RangeError(`Expected ${header.length} tabular rows, but found more`)
       }
       else if (hasDelimiter) {
         // Has both colon and delimiter - check which comes first
@@ -292,7 +292,7 @@ function decodeTabularArray(
         const delimiterPos = nextLine.content.indexOf(header.delimiter)
         if (delimiterPos < colonPos) {
           // Delimiter before colon = data row
-          throw new Error(`Expected ${header.length} tabular rows, but found more`)
+          throw new RangeError(`Expected ${header.length} tabular rows, but found more`)
         }
         // Colon before delimiter = key-value pair, OK
       }
@@ -315,7 +315,7 @@ function decodeListItem(
 ): JsonValue {
   const line = cursor.next()
   if (!line) {
-    throw new Error('Expected list item')
+    throw new ReferenceError('Expected list item')
   }
 
   const afterHyphen = line.content.slice(LIST_ITEM_PREFIX.length)
@@ -382,7 +382,7 @@ function decodeFirstFieldOnHyphen(
 
 function assertExpectedCount(actual: number, expected: number, what: string, options: ResolvedDecodeOptions): void {
   if (options.strict && actual !== expected) {
-    throw new Error(`Expected ${expected} ${what}, but got ${actual}`)
+    throw new RangeError(`Expected ${expected} ${what}, but got ${actual}`)
   }
 }
 

src/index.ts

@@ -36,7 +36,7 @@ export function decode(input: string, options?: DecodeOptions): JsonValue {
   const lines = toParsedLines(input, resolved.indent)
 
   if (lines.length === 0) {
-    throw new Error('Cannot decode empty input')
+    throw new TypeError('Cannot decode empty input: input must be a non-empty string')
   }
 
   const cursor = new LineCursor(lines)

src/parser.ts

@@ -256,7 +256,7 @@ export function parseStringLiteral(token: string): string {
       if (trimmed[i] === DOUBLE_QUOTE) {
         // Found closing quote
         if (i !== trimmed.length - 1) {
-          throw new Error('Unexpected characters after closing quote')
+          throw new SyntaxError('Unexpected characters after closing quote')
         }
         const content = trimmed.slice(1, i)
         return unescapeString(content)
@@ -265,7 +265,7 @@ export function parseStringLiteral(token: string): string {
     }
 
     // If we get here, no closing quote was found
-    throw new Error('Unterminated string: missing closing quote')
+    throw new SyntaxError('Unterminated string: missing closing quote')
   }
 
   return trimmed
@@ -278,7 +278,7 @@ export function unescapeString(value: string): string {
   while (i < value.length) {
     if (value[i] === BACKSLASH) {
       if (i + 1 >= value.length) {
-        throw new Error('Invalid escape sequence: backslash at end of string')
+        throw new SyntaxError('Invalid escape sequence: backslash at end of string')
       }
 
       const next = value[i + 1]
@@ -308,7 +308,7 @@ export function unescapeString(value: string): string {
         continue
       }
 
-      throw new Error(`Invalid escape sequence: \\${next}`)
+      throw new SyntaxError(`Invalid escape sequence: \\${next}`)
     }
 
     result += value[i]
@@ -326,7 +326,7 @@ export function parseUnquotedKey(content: string, start: number): { key: string,
 
   // Validate that a colon was found
   if (end >= content.length || content[end] !== COLON) {
-    throw new Error('Missing colon after key')
+    throw new SyntaxError('Missing colon after key')
   }
 
   const key = content.slice(start, end).trim()
@@ -355,7 +355,7 @@ export function parseQuotedKey(content: string, start: number): { key: string, e
 
       // Validate and skip colon after quoted key
       if (end >= content.length || content[end] !== COLON) {
-        throw new Error('Missing colon after key')
+        throw new SyntaxError('Missing colon after key')
       }
       end++
 
@@ -366,7 +366,7 @@ export function parseQuotedKey(content: string, start: number): { key: string, e
     i++
   }
 
-  throw new Error('Unterminated quoted key')
+  throw new SyntaxError('Unterminated quoted key')
 }
 
 export function parseKeyToken(content: string, start: number): { key: string, end: number } {