test: add case for unquoted invalid numeric formats as strings

src/encode/encoders.ts

@@ -1,26 +1,7 @@
-import type {
-  Depth,
-  JsonArray,
-  JsonObject,
-  JsonPrimitive,
-  JsonValue,
-  ResolvedEncodeOptions,
-} from '../types'
+import type { Depth, JsonArray, JsonObject, JsonPrimitive, JsonValue, ResolvedEncodeOptions } from '../types'
 import { LIST_ITEM_MARKER } from '../constants'
-import {
-  isArrayOfArrays,
-  isArrayOfObjects,
-  isArrayOfPrimitives,
-  isJsonArray,
-  isJsonObject,
-  isJsonPrimitive,
-} from './normalize'
-import {
-  encodeAndJoinPrimitives,
-  encodeKey,
-  encodePrimitive,
-  formatHeader,
-} from './primitives'
+import { isArrayOfArrays, isArrayOfObjects, isArrayOfPrimitives, isJsonArray, isJsonObject, isJsonPrimitive } from './normalize'
+import { encodeAndJoinPrimitives, encodeKey, encodePrimitive, formatHeader } from './primitives'
 import { LineWriter } from './writer'
 
 // #region Encode normalized JsonValue

src/encode/normalize.ts

@@ -1,9 +1,4 @@
-import type {
-  JsonArray,
-  JsonObject,
-  JsonPrimitive,
-  JsonValue,
-} from '../types'
+import type { JsonArray, JsonObject, JsonPrimitive, JsonValue } from '../types'
 
 // #region Normalization (unknown → JsonValue)
 

src/encode/primitives.ts

@@ -1,14 +1,7 @@
 import type { JsonPrimitive } from '../types'
-import {
-  BACKSLASH,
-  COMMA,
-  DEFAULT_DELIMITER,
-  DOUBLE_QUOTE,
-  FALSE_LITERAL,
-  LIST_ITEM_MARKER,
-  NULL_LITERAL,
-  TRUE_LITERAL,
-} from '../constants'
+import { COMMA, DEFAULT_DELIMITER, DOUBLE_QUOTE, NULL_LITERAL } from '../constants'
+import { escapeString } from '../shared/string-utils'
+import { isSafeUnquoted, isValidUnquotedKey } from '../shared/validation'
 
 // #region Primitive encoding
 
@@ -36,74 +29,6 @@ export function encodeStringLiteral(value: string, delimiter: string = COMMA): s
   return `${DOUBLE_QUOTE}${escapeString(value)}${DOUBLE_QUOTE}`
 }
 
-export function escapeString(value: string): string {
-  return value
-    .replace(/\\/g, `${BACKSLASH}${BACKSLASH}`)
-    .replace(/"/g, `${BACKSLASH}${DOUBLE_QUOTE}`)
-    .replace(/\n/g, `${BACKSLASH}n`)
-    .replace(/\r/g, `${BACKSLASH}r`)
-    .replace(/\t/g, `${BACKSLASH}t`)
-}
-
-export function isSafeUnquoted(value: string, delimiter: string = COMMA): boolean {
-  if (!value) {
-    return false
-  }
-
-  if (isPaddedWithWhitespace(value)) {
-    return false
-  }
-
-  if (value === TRUE_LITERAL || value === FALSE_LITERAL || value === NULL_LITERAL) {
-    return false
-  }
-
-  if (isNumericLike(value)) {
-    return false
-  }
-
-  // Check for colon (always structural)
-  if (value.includes(':')) {
-    return false
-  }
-
-  // Check for quotes and backslash (always need escaping)
-  if (value.includes('"') || value.includes('\\')) {
-    return false
-  }
-
-  // Check for brackets and braces (always structural)
-  if (/[[\]{}]/.test(value)) {
-    return false
-  }
-
-  // Check for control characters (newline, carriage return, tab - always need quoting/escaping)
-  if (/[\n\r\t]/.test(value)) {
-    return false
-  }
-
-  // Check for the active delimiter
-  if (value.includes(delimiter)) {
-    return false
-  }
-
-  // Check for hyphen at start (list marker)
-  if (value.startsWith(LIST_ITEM_MARKER)) {
-    return false
-  }
-
-  return true
-}
-
-function isNumericLike(value: string): boolean {
-  // Match numbers like: 42, -3.14, 1e-6, 05, etc.
-  return /^-?\d+(?:\.\d+)?(?:e[+-]?\d+)?$/i.test(value) || /^0\d+$/.test(value)
-}
-
-function isPaddedWithWhitespace(value: string): boolean {
-  return value !== value.trim()
-}
-
 // #endregion
 
 // #region Key encoding
@@ -116,10 +41,6 @@ export function encodeKey(key: string): string {
   return `${DOUBLE_QUOTE}${escapeString(key)}${DOUBLE_QUOTE}`
 }
 
-function isValidUnquotedKey(key: string): boolean {
-  return /^[A-Z_][\w.]*$/i.test(key)
-}
-
 // #endregion
 
 // #region Value joining
@@ -132,9 +53,6 @@ export function encodeAndJoinPrimitives(values: readonly JsonPrimitive[], delimi
 
 // #region Header formatters
 
-/**
- * Header formatter for arrays and tables with optional key prefix and field names
- */
 export function formatHeader(
   length: number,
   options?: {