n2words/src/gu-IN.js

Convert numbers to words in 70+ languages with zero dependencies. Supports BigInt, decimals, and browser/Node.js environments.

/**
 * Gujarati (India) language converter
 *
 * CLDR: gu-IN | Gujarati as used in India
 *
 * Key features:
 * - Indian numbering system (હજાર, લાખ, કરોડ)
 * - Gujarati script
 * - 3-2-2 grouping pattern (last 3 digits, then groups of 2)
 * - Complete word forms for 0-99
 * - Per-digit decimal reading
 */

import { parseCardinalValue } from './utils/parse-cardinal.js'
import { parseCurrencyValue } from './utils/parse-currency.js'
import { parseOrdinalValue } from './utils/parse-ordinal.js'
import { checkMax } from './utils/check-max.js'
import { indian } from './utils/scale.js'

// ============================================================================
// Vocabulary
// ============================================================================

const ZERO = 'શૂન્ય'
const NEGATIVE = 'ઋણ'
const DECIMAL_SEP = 'દશાંશ'
const HUNDRED = 'સો'

// ============================================================================
// Ordinal Vocabulary
// ============================================================================

// Ordinal suffix (adds to cardinal for numbers >= 7)
const ORDINAL_SUFFIX = 'મું'

// Special ordinals for first few numbers (1-6 have irregular forms)
const ORDINAL_SPECIAL = ['', 'પહેલું', 'બીજું', 'ત્રીજું', 'ચોથું', 'પાંચમું', 'છઠ્ઠું']

// ============================================================================
// Currency Vocabulary (Indian Rupee)
// ============================================================================

// Rupee: singular/plural
const RUPEE = 'રૂપિયો'
const RUPEES = 'રૂપિયા'

// Paisa: singular/plural
const PAISA = 'પૈસો'
const PAISE = 'પૈસા'

const BELOW_HUNDRED = [
  'શૂન્ય', 'એક', 'બે', 'ત્રણ', 'ચાર', 'પાંચ', 'છ', 'સાત', 'આઠ', 'નવ',
  'દસ', 'અગિયાર', 'બાર', 'તેર', 'ચૌદ', 'પંદર', 'સોળ', 'સત્તર', 'અઢાર', 'ઓગણીસ',
  'વીસ', 'એકવીસ', 'બાવીસ', 'ત્રેવીસ', 'ચોવીસ', 'પચીસ', 'છવ્વીસ', 'સત્તાવીસ', 'અઠ્ઠાવીસ', 'ઓગણત્રીસ',
  'ત્રીસ', 'એકત્રીસ', 'બત્રીસ', 'તેત્રીસ', 'ચોત્રીસ', 'પાંત્રીસ', 'છત્રીસ', 'સાડત્રીસ', 'અડત્રીસ', 'ઓગણચાલીસ',
  'ચાલીસ', 'એકતાલીસ', 'બેતાળીસ', 'ત્રેતાળીસ', 'ચુંમાલીસ', 'પિસ્તાલીસ', 'છેતાળીસ', 'સુડતાળીસ', 'અડતાળીસ', 'ઓગણપચાસ',
  'પચાસ', 'એકાવન', 'બાવન', 'ત્રેપન', 'ચોપન', 'પંચાવન', 'છપ્પન', 'સત્તાવન', 'અઠ્ઠાવન', 'ઓગણસાઠ',
  'સાઠ', 'એકસઠ', 'બાસઠ', 'ત્રેસઠ', 'ચોસઠ', 'પાંસઠ', 'છાસઠ', 'સડસઠ', 'અડસઠ', 'અગણોસિત્તેર',
  'સિત્તેર', 'એકોતેર', 'બોતેર', 'તોતેર', 'ચુમોતેર', 'પંચોતેર', 'છોતેર', 'સિત્યોતેર', 'ઇઠ્યોતેર', 'ઓગણાએંસી',
  'એંસી', 'એક્યાસી', 'બ્યાસી', 'ત્યાસી', 'ચોર્યાસી', 'પંચાસી', 'છ્યાસી', 'સિત્યાસી', 'અઠ્યાસી', 'નેવ્યાસી',
  'નેવું', 'એકાણું', 'બાણું', 'ત્રાણું', 'ચોરાણું', 'પંચાણું', 'છન્નું', 'સત્તાણું', 'અઠ્ઠાણું', 'નવ્વાણું',
]

// Scale words: index 0 = units (empty), 1 = thousand, 2 = lakh, 3 = crore, etc.
const SCALE_WORDS = ['', 'હજાર', 'લાખ', 'કરોડ', 'અબજ', 'ખરબ', 'નીલ', 'પદ્મ', 'શંખ']

// 3-2-2 Indian grouping: a 3-digit base segment, then 2 digits per scale word
// (SCALE_WORDS[0] = '' is the units slot). Past the table the scale word is
// dropped, which collapses the magnitude — so cap there.
export const cardinalMax = indian(SCALE_WORDS.length)
export const ordinalMax = indian(SCALE_WORDS.length)
export const currencyMax = indian(SCALE_WORDS.length)

// ============================================================================
// Segment Building
// ============================================================================

/**
 * Builds words for a 0-999 segment.
 * @param {number} n - Segment value (0-999)
 * @returns {string} Gujarati words for the segment
 */
function buildSegment(n) {
  if (n === 0) return ''
  if (n < 100) return BELOW_HUNDRED[n]

  const hundreds = Math.trunc(n / 100)
  const remainder = n % 100

  if (remainder === 0) {
    return BELOW_HUNDRED[hundreds] + ' ' + HUNDRED
  }
  return BELOW_HUNDRED[hundreds] + ' ' + HUNDRED + ' ' + BELOW_HUNDRED[remainder]
}

// ============================================================================
// Conversion Functions
// ============================================================================

/**
 * Converts a non-negative integer to Gujarati words.
 *
 * Uses BigInt modulo for segment extraction (faster than string slicing).
 * South Asian 3-2-2 grouping: first 3 digits, then groups of 2.
 * @param {bigint} n - Non-negative integer to convert
 * @returns {string} Gujarati words
 */
function integerToWords(n) {
  if (n === 0n) return ZERO

  // Fast path: numbers < 1000 (direct lookup)
  if (n < 1000n) {
    return buildSegment(Number(n))
  }

  // Extract segments using BigInt modulo
  const segments = []
  segments.push(Number(n % 1000n))
  let temp = n / 1000n

  while (temp > 0n) {
    segments.push(Number(temp % 100n))
    temp = temp / 100n
  }

  // Build result string (process from most-significant to least)
  const words = []
  for (let i = segments.length - 1; i >= 0; i--) {
    const segment = segments[i]
    if (segment === 0) continue

    if (i === 0) {
      words.push(buildSegment(segment))
    }
    else {
      words.push(BELOW_HUNDRED[segment])
    }

    if (i > 0 && SCALE_WORDS[i]) {
      words.push(SCALE_WORDS[i])
    }
  }

  return words.join(' ')
}

/**
 * Converts the fractional digits to per-digit Gujarati words.
 * @param {string} decimalPart - Decimal digits as a string
 * @returns {string} Gujarati words for each digit
 */
function decimalPartToWords(decimalPart) {
  // Per-digit decimal reading
  const digits = []
  for (const char of decimalPart) {
    const d = parseInt(char, 10)
    digits.push(d === 0 ? ZERO : BELOW_HUNDRED[d])
  }
  return digits.join(' ')
}

/**
 * Converts a numeric value to Gujarati words.
 * @param {number | string | bigint} value - The numeric value to convert
 * @returns {string} The number in Gujarati words
 */
function toCardinal(value) {
  const { isNegative, integerPart, decimalPart } = parseCardinalValue(value)
  // The fraction is spelled digit by digit, so only the integer part has a ceiling.
  checkMax(integerPart, cardinalMax)

  let result = ''

  if (isNegative) {
    result = NEGATIVE + ' '
  }

  result += integerToWords(integerPart)

  if (decimalPart) {
    result += ' ' + DECIMAL_SEP + ' ' + decimalPartToWords(decimalPart)
  }

  return result
}

// ============================================================================
// ORDINAL: toOrdinal(value)
// ============================================================================

/**
 * Converts a positive integer to Gujarati ordinal words.
 *
 * Gujarati ordinals: First 6 are irregular, then add -મું suffix.
 * @param {bigint} n - Positive integer to convert
 * @returns {string} Gujarati ordinal words
 */
function integerToOrdinal(n) {
  // Special ordinals for 1-6
  if (n >= 1n && n <= 6n) {
    return ORDINAL_SPECIAL[Number(n)]
  }

  // For 7 and above, add suffix to cardinal
  const cardinal = integerToWords(n)
  return cardinal + ORDINAL_SUFFIX
}

/**
 * Converts a numeric value to Gujarati ordinal words.
 * @param {number | string | bigint} value - The numeric value to convert (positive integer)
 * @returns {string} The number as ordinal words
 * @throws {TypeError} If value is not a valid numeric type
 * @throws {RangeError} If value is negative, zero, or has a decimal part
 * @example
 * toOrdinal(1)    // 'પહેલું'
 * toOrdinal(2)    // 'બીજું'
 * toOrdinal(10)   // 'દસમું'
 */
function toOrdinal(value) {
  const integerPart = parseOrdinalValue(value)
  // Ordinals build on the cardinal speller, so they share its ceiling.
  checkMax(integerPart, ordinalMax)
  return integerToOrdinal(integerPart)
}

// ============================================================================
// CURRENCY: toCurrency(value, options?)
// ============================================================================

/**
 * Converts a numeric value to Gujarati currency words (Indian Rupee).
 * @param {number | string | bigint} value - The currency amount to convert
 * @returns {string} The amount in Gujarati currency words
 * @throws {TypeError} If value is not a valid numeric type
 * @throws {Error} If value is not a valid number format
 * @example
 * toCurrency(42.50)  // 'બેતાળીસ રૂપિયા પચાસ પૈસા'
 * toCurrency(1)      // 'એક રૂપિયો'
 * toCurrency(0.01)   // 'એક પૈસો'
 */
function toCurrency(value) {
  const { isNegative, dollars: rupees, cents: paise } = parseCurrencyValue(value)
  checkMax(rupees, currencyMax)

  // Build result
  let result = ''
  if (isNegative) result = NEGATIVE + ' '

  // Rupees part - show if non-zero, or if no paise
  if (rupees > 0n || paise === 0n) {
    result += integerToWords(rupees)
    // Singular for 1 rupee, plural otherwise
    result += ' ' + (rupees === 1n ? RUPEE : RUPEES)
  }

  // Paise part
  if (paise > 0n) {
    if (rupees > 0n) {
      result += ' '
    }
    result += integerToWords(paise)
    // Singular for 1 paisa, plural otherwise
    result += ' ' + (paise === 1n ? PAISA : PAISE)
  }

  return result
}

// ============================================================================
// Exports
// ============================================================================

export { toCardinal, toOrdinal, toCurrency }