refactor: decoding source files

src/decode/decoders.ts

@@ -1,6 +1,6 @@
-import type { LineCursor } from './scanner'
 import type {
   ArrayHeaderInfo,
+  Delimiter,
   Depth,
   JsonArray,
   JsonObject,
@@ -8,12 +8,13 @@ import type {
   JsonValue,
   ParsedLine,
   ResolvedDecodeOptions,
-} from './types'
+} from '../types'
+import type { LineCursor } from './scanner'
 import {
   COLON,
   DEFAULT_DELIMITER,
   LIST_ITEM_PREFIX,
-} from './constants'
+} from '../constants'
 import {
   isArrayHeaderAfterHyphen,
   isObjectFirstFieldAfterHyphen,
@@ -23,6 +24,12 @@ import {
   parseKeyToken,
   parsePrimitiveToken,
 } from './parser'
+import { findClosingQuote } from './string-utils'
+import {
+  assertExpectedCount,
+  validateNoExtraListItems,
+  validateNoExtraTabularRows,
+} from './validation'
 
 // #region Entry decoding
 
@@ -33,7 +40,7 @@ export function decodeValueFromLines(cursor: LineCursor, options: ResolvedDecode
   }
 
   // Check for root array
-  if (isRootArrayHeaderLine(first)) {
+  if (isArrayHeaderAfterHyphen(first.content)) {
     const headerInfo = parseArrayHeaderLine(first.content, DEFAULT_DELIMITER)
     if (headerInfo) {
       cursor.advance() // Move past the header line
@@ -50,29 +57,18 @@ export function decodeValueFromLines(cursor: LineCursor, options: ResolvedDecode
   return decodeObject(cursor, 0, options)
 }
 
-function isRootArrayHeaderLine(line: ParsedLine): boolean {
-  return isArrayHeaderAfterHyphen(line.content)
-}
-
 function isKeyValueLine(line: ParsedLine): boolean {
   const content = line.content
   // Look for unquoted colon or quoted key followed by colon
   if (content.startsWith('"')) {
-    // Quoted key
-    let i = 1
-    while (i < content.length) {
-      if (content[i] === '\\' && i + 1 < content.length) {
-        i += 2
-        continue
-      }
-      if (content[i] === '"') {
-        // Found end of quoted key, check for colon
-        return content[i + 1] === COLON
-      }
-      i++
-    }
+    // Quoted key - find the closing quote
+    const closingQuoteIndex = findClosingQuote(content, 0)
+    if (closingQuoteIndex === -1) {
       return false
     }
+    // Check if there's a colon after the quoted key
+    return closingQuoteIndex + 1 < content.length && content[closingQuoteIndex + 1] === COLON
+  }
   else {
     // Unquoted key - look for first colon not inside quotes
     return content.includes(COLON)
@@ -227,11 +223,8 @@ function decodeListArray(
   assertExpectedCount(items.length, header.length, 'list array items', options)
 
   // In strict mode, check for extra items
-  if (options.strict && !cursor.atEnd()) {
-    const nextLine = cursor.peek()
-    if (nextLine && nextLine.depth === itemDepth && nextLine.content.startsWith(LIST_ITEM_PREFIX)) {
-      throw new RangeError(`Expected ${header.length} list array items, but found more`)
-    }
+  if (options.strict) {
+    validateNoExtraListItems(cursor, itemDepth, header.length)
   }
 
   return items
@@ -274,30 +267,8 @@ function decodeTabularArray(
   assertExpectedCount(objects.length, header.length, 'tabular rows', options)
 
   // In strict mode, check for extra rows
-  if (options.strict && !cursor.atEnd()) {
-    const nextLine = cursor.peek()
-    if (nextLine && nextLine.depth === rowDepth && !nextLine.content.startsWith(LIST_ITEM_PREFIX)) {
-      // A key-value pair has a colon (and if it has delimiter, colon comes first)
-      // A data row either has no colon, or has delimiter before colon
-      const hasColon = nextLine.content.includes(COLON)
-      const hasDelimiter = nextLine.content.includes(header.delimiter)
-
-      if (!hasColon) {
-        // No colon = data row (for single-field tables)
-        throw new RangeError(`Expected ${header.length} tabular rows, but found more`)
-      }
-      else if (hasDelimiter) {
-        // Has both colon and delimiter - check which comes first
-        const colonPos = nextLine.content.indexOf(COLON)
-        const delimiterPos = nextLine.content.indexOf(header.delimiter)
-        if (delimiterPos < colonPos) {
-          // Delimiter before colon = data row
-          throw new RangeError(`Expected ${header.length} tabular rows, but found more`)
-        }
-        // Colon before delimiter = key-value pair, OK
-      }
-      // Has colon but no delimiter = key-value pair, OK
-    }
+  if (options.strict) {
+    validateNoExtraTabularRows(cursor, rowDepth, header)
   }
 
   return objects
@@ -310,7 +281,7 @@ function decodeTabularArray(
 function decodeListItem(
   cursor: LineCursor,
   baseDepth: Depth,
-  activeDelimiter: string,
+  activeDelimiter: Delimiter,
   options: ResolvedDecodeOptions,
 ): JsonValue {
   const line = cursor.next()
@@ -322,7 +293,7 @@ function decodeListItem(
 
   // Check for array header after hyphen
   if (isArrayHeaderAfterHyphen(afterHyphen)) {
-    const arrayHeader = parseArrayHeaderLine(afterHyphen, activeDelimiter as any)
+    const arrayHeader = parseArrayHeaderLine(afterHyphen, activeDelimiter)
     if (arrayHeader) {
       return decodeArrayFromHeader(arrayHeader.header, arrayHeader.inlineValues, cursor, baseDepth, options)
     }
@@ -344,7 +315,7 @@ function decodeObjectFromListItem(
   options: ResolvedDecodeOptions,
 ): JsonObject {
   const afterHyphen = firstLine.content.slice(LIST_ITEM_PREFIX.length)
-  const { key, value, followDepth } = decodeFirstFieldOnHyphen(afterHyphen, cursor, baseDepth, options)
+  const { key, value, followDepth } = decodeKeyValue(afterHyphen, cursor, baseDepth, options)
 
   const obj: JsonObject = { [key]: value }
 
@@ -367,23 +338,4 @@ function decodeObjectFromListItem(
   return obj
 }
 
-function decodeFirstFieldOnHyphen(
-  rest: string,
-  cursor: LineCursor,
-  baseDepth: Depth,
-  options: ResolvedDecodeOptions,
-): { key: string, value: JsonValue, followDepth: Depth } {
-  return decodeKeyValue(rest, cursor, baseDepth, options)
-}
-
-// #endregion
-
-// #region Validation
-
-function assertExpectedCount(actual: number, expected: number, what: string, options: ResolvedDecodeOptions): void {
-  if (options.strict && actual !== expected) {
-    throw new RangeError(`Expected ${expected} ${what}, but got ${actual}`)
-  }
-}
-
 // #endregion

src/decode/parser.ts

@@ -2,7 +2,7 @@ import type {
   ArrayHeaderInfo,
   Delimiter,
   JsonPrimitive,
-} from './types'
+} from '../types'
 import {
   BACKSLASH,
   CARRIAGE_RETURN,
@@ -20,7 +20,8 @@ import {
   PIPE,
   TAB,
   TRUE_LITERAL,
-} from './constants'
+} from '../constants'
+import { findClosingQuote, hasUnquotedChar } from './string-utils'
 
 // #region Array header parsing
 
@@ -246,26 +247,19 @@ export function parseStringLiteral(token: string): string {
 
   if (trimmed.startsWith(DOUBLE_QUOTE)) {
     // Find the closing quote, accounting for escaped quotes
-    let i = 1
-    while (i < trimmed.length) {
-      if (trimmed[i] === BACKSLASH && i + 1 < trimmed.length) {
-        // Skip escaped character
-        i += 2
-        continue
-      }
-      if (trimmed[i] === DOUBLE_QUOTE) {
-        // Found closing quote
-        if (i !== trimmed.length - 1) {
-          throw new SyntaxError('Unexpected characters after closing quote')
-        }
-        const content = trimmed.slice(1, i)
-        return unescapeString(content)
-      }
-      i++
+    const closingQuoteIndex = findClosingQuote(trimmed, 0)
+
+    if (closingQuoteIndex === -1) {
+      // No closing quote was found
+      throw new SyntaxError('Unterminated string: missing closing quote')
     }
 
-    // If we get here, no closing quote was found
-    throw new SyntaxError('Unterminated string: missing closing quote')
+    if (closingQuoteIndex !== trimmed.length - 1) {
+      throw new SyntaxError('Unexpected characters after closing quote')
+    }
+
+    const content = trimmed.slice(1, closingQuoteIndex)
+    return unescapeString(content)
   }
 
   return trimmed
@@ -338,20 +332,17 @@ export function parseUnquotedKey(content: string, start: number): { key: string,
 }
 
 export function parseQuotedKey(content: string, start: number): { key: string, end: number } {
-  let i = start + 1 // Skip opening quote
-  let keyContent = ''
+  // Find the closing quote, accounting for escaped quotes
+  const closingQuoteIndex = findClosingQuote(content, start)
 
-  while (i < content.length) {
-    if (content[i] === BACKSLASH && i + 1 < content.length) {
-      keyContent += content[i]! + content[i + 1]
-      i += 2
-      continue
+  if (closingQuoteIndex === -1) {
+    throw new SyntaxError('Unterminated quoted key')
   }
 
-    if (content[i] === DOUBLE_QUOTE) {
-      // Found closing quote
+  // Extract and unescape the key content
+  const keyContent = content.slice(start + 1, closingQuoteIndex)
   const key = unescapeString(keyContent)
-      let end = i + 1
+  let end = closingQuoteIndex + 1
 
   // Validate and skip colon after quoted key
   if (end >= content.length || content[end] !== COLON) {
@@ -362,13 +353,6 @@ export function parseQuotedKey(content: string, start: number): { key: string, e
   return { key, end }
 }
 
-    keyContent += content[i]
-    i++
-  }
-
-  throw new SyntaxError('Unterminated quoted key')
-}
-
 export function parseKeyToken(content: string, start: number): { key: string, end: number } {
   if (content[start] === DOUBLE_QUOTE) {
     return parseQuotedKey(content, start)
@@ -383,11 +367,11 @@ export function parseKeyToken(content: string, start: number): { key: string, en
 // #region Array content detection helpers
 
 export function isArrayHeaderAfterHyphen(content: string): boolean {
-  return content.trim().startsWith(OPEN_BRACKET) && content.includes(COLON)
+  return content.trim().startsWith(OPEN_BRACKET) && hasUnquotedChar(content, COLON)
 }
 
 export function isObjectFirstFieldAfterHyphen(content: string): boolean {
-  return content.includes(COLON)
+  return hasUnquotedChar(content, COLON)
 }
 
 // #endregion

src/decode/scanner.ts

@@ -1,5 +1,5 @@
-import type { Depth, ParsedLine } from './types'
-import { SPACE } from './constants'
+import type { Depth, ParsedLine } from '../types'
+import { SPACE } from '../constants'
 
 export class LineCursor {
   private lines: ParsedLine[]
@@ -33,6 +33,21 @@ export class LineCursor {
   get length(): number {
     return this.lines.length
   }
+
+  peekAtDepth(targetDepth: Depth): ParsedLine | undefined {
+    const line = this.peek()
+    if (!line || line.depth < targetDepth) {
+      return undefined
+    }
+    if (line.depth === targetDepth) {
+      return line
+    }
+    return undefined
+  }
+
+  hasMoreAtDepth(targetDepth: Depth): boolean {
+    return this.peekAtDepth(targetDepth) !== undefined
+  }
 }
 
 export function toParsedLines(source: string, indentSize: number): ParsedLine[] {

src/decode/string-utils.ts

@@ -0,0 +1,96 @@
+import { BACKSLASH, DOUBLE_QUOTE } from '../constants'
+
+/**
+ * Finds the index of the closing double quote in a string, accounting for escape sequences.
+ *
+ * @param content The string to search in
+ * @param start The index of the opening quote
+ * @returns The index of the closing quote, or -1 if not found
+ */
+export function findClosingQuote(content: string, start: number): number {
+  let i = start + 1
+  while (i < content.length) {
+    if (content[i] === BACKSLASH && i + 1 < content.length) {
+      // Skip escaped character
+      i += 2
+      continue
+    }
+    if (content[i] === DOUBLE_QUOTE) {
+      return i
+    }
+    i++
+  }
+  return -1 // Not found
+}
+
+/**
+ * Checks if a string contains a specific character outside of quoted sections.
+ *
+ * @param content The string to check
+ * @param char The character to look for
+ * @returns true if the character exists outside quotes, false otherwise
+ */
+export function hasUnquotedChar(content: string, char: string): boolean {
+  return findUnquotedChar(content, char) !== -1
+}
+
+/**
+ * Finds the index of a specific character outside of quoted sections.
+ *
+ * @param content The string to search in
+ * @param char The character to look for
+ * @param start Optional starting index (defaults to 0)
+ * @returns The index of the character, or -1 if not found outside quotes
+ */
+export function findUnquotedChar(content: string, char: string, start = 0): number {
+  let inQuotes = false
+  let i = start
+
+  while (i < content.length) {
+    if (content[i] === BACKSLASH && i + 1 < content.length && inQuotes) {
+      // Skip escaped character
+      i += 2
+      continue
+    }
+
+    if (content[i] === DOUBLE_QUOTE) {
+      inQuotes = !inQuotes
+      i++
+      continue
+    }
+
+    if (content[i] === char && !inQuotes) {
+      return i
+    }
+
+    i++
+  }
+
+  return -1
+}
+
+/**
+ * Checks if a string starts and ends with double quotes.
+ *
+ * @param content The string to check
+ * @returns true if the string is quoted, false otherwise
+ */
+export function isQuotedString(content: string): boolean {
+  const trimmed = content.trim()
+  return trimmed.startsWith(DOUBLE_QUOTE) && trimmed.endsWith(DOUBLE_QUOTE) && trimmed.length >= 2
+}
+
+/**
+ * Skips whitespace characters starting from a given index.
+ *
+ * @param content The string to process
+ * @param start The starting index
+ * @returns The index of the first non-whitespace character, or content.length if all whitespace
+ */
+export function skipWhitespace(content: string, start: number): number {
+  let i = start
+  while (i < content.length && /\s/.test(content[i]!)) {
+    i++
+  }
+  return i
+}

src/decode/validation.ts

@@ -0,0 +1,97 @@
+import type { ArrayHeaderInfo, Delimiter, Depth, ResolvedDecodeOptions } from '../types'
+import type { LineCursor } from './scanner'
+import { COLON, LIST_ITEM_PREFIX } from '../constants'
+
+/**
+ * Asserts that the actual count matches the expected count in strict mode.
+ *
+ * @param actual The actual count
+ * @param expected The expected count
+ * @param itemType The type of items being counted (e.g., 'list array items', 'tabular rows')
+ * @param options Decode options
+ * @throws RangeError if counts don't match in strict mode
+ */
+export function assertExpectedCount(
+  actual: number,
+  expected: number,
+  itemType: string,
+  options: ResolvedDecodeOptions,
+): void {
+  if (options.strict && actual !== expected) {
+    throw new RangeError(`Expected ${expected} ${itemType}, but got ${actual}`)
+  }
+}
+
+/**
+ * Validates that there are no extra list items beyond the expected count.
+ *
+ * @param cursor The line cursor
+ * @param itemDepth The expected depth of items
+ * @param expectedCount The expected number of items
+ * @throws RangeError if extra items are found
+ */
+export function validateNoExtraListItems(
+  cursor: LineCursor,
+  itemDepth: Depth,
+  expectedCount: number,
+): void {
+  if (cursor.atEnd())
+    return
+
+  const nextLine = cursor.peek()
+  if (nextLine && nextLine.depth === itemDepth && nextLine.content.startsWith(LIST_ITEM_PREFIX)) {
+    throw new RangeError(`Expected ${expectedCount} list array items, but found more`)
+  }
+}
+
+/**
+ * Checks if a line represents a data row (as opposed to a key-value pair) in a tabular array.
+ *
+ * @param content The line content
+ * @param delimiter The delimiter used in the table
+ * @returns true if the line is a data row, false if it's a key-value pair
+ */
+export function isDataRow(content: string, delimiter: Delimiter): boolean {
+  const colonPos = content.indexOf(COLON)
+  const delimiterPos = content.indexOf(delimiter)
+
+  // No colon = definitely a data row
+  if (colonPos === -1) {
+    return true
+  }
+
+  // Has delimiter and it comes before colon = data row
+  if (delimiterPos !== -1 && delimiterPos < colonPos) {
+    return true
+  }
+
+  // Colon before delimiter or no delimiter = key-value pair
+  return false
+}
+
+/**
+ * Validates that there are no extra tabular rows beyond the expected count.
+ *
+ * @param cursor The line cursor
+ * @param rowDepth The expected depth of rows
+ * @param header The array header info containing length and delimiter
+ * @throws RangeError if extra rows are found
+ */
+export function validateNoExtraTabularRows(
+  cursor: LineCursor,
+  rowDepth: Depth,
+  header: ArrayHeaderInfo,
+): void {
+  if (cursor.atEnd())
+    return
+
+  const nextLine = cursor.peek()
+  if (
+    nextLine
+    && nextLine.depth === rowDepth
+    && !nextLine.content.startsWith(LIST_ITEM_PREFIX)
+    && isDataRow(nextLine.content, header.delimiter)
+  ) {
+    throw new RangeError(`Expected ${header.length} tabular rows, but found more`)
+  }
+}

src/index.ts

@@ -6,10 +6,10 @@ import type {
   ResolvedEncodeOptions,
 } from './types'
 import { DEFAULT_DELIMITER } from './constants'
-import { decodeValueFromLines } from './decoders'
+import { decodeValueFromLines } from './decode/decoders'
 import { encodeValue } from './encoders'
 import { normalizeValue } from './normalize'
-import { LineCursor, toParsedLines } from './scanner'
+import { LineCursor, toParsedLines } from './decode/scanner'
 
 export { DEFAULT_DELIMITER, DELIMITERS } from './constants'
 export type {