This package converts numbers to their written forms in French language

  npm install french-numbers-to-words

  const myNumber = new FrenchNumbersToWords(12345, 'fr').result
  // The result is an object like this
  {
    parts: [
      { number: 12, text: 'douze', unit: 'mille' },
      { number: 345, text: 'trois-cent-quarante-cinq', unit: '' }
    ],
    fullText: 'douze-mille trois-cent-quarante-cinq'
  }

less than 16 follow no rules but each has a specific name."zéro", "un", "deux", "trois", "quatre", "cinq", "six", "sept", "huit", "neuf", "dix", "onze", "douze", "treize", "quatorze", "quinze", "seize"(from 0 to 16)

as French up to 60, or using Belgium-French (septante, huitante, nonante), up to 90, follow the same pattern :

• "dix",
• "vingt",
• "trente",
• "quarante",
• "cinquante",
• "soixante",
• "septante",
• "huitante",
• "nonante"(from 10 to 90)"huitante" could also be "octante". In French from France, the pattern change at 70:
• 70 = 60 + 10 = "soixante-dix"
• 80 = 4 * 20 = "quatre-vingts"
• 90 = 4 * 20 + 10 = "quatre-vingt-dix"

The rule is easy:

• 22 = 20 + 2 = "vingt-deux", with a dash in between From 17 to 19, it follows this rule
• 17 = 10 + 7 = "dix-sept"

The rule is the same as above, but with "-et-" which means "and" instead of "-":

• 21 = "vingt-et-un" Before 1990, the writing was "vingt et un" but since the 1990 simplification reform, all words used for numbers are joined-up with dashes.

• 74 = 60 + 14 = "soixante-quatorze"
• 77 = 60 + 17 = 60 + 10 + 7 = "soixante-dix-sept"
• 95 = 4 * 20 + 15 = "quatre-vingt-quinze"
• 99 = 4 * 20 + 10 + 9 = "quatre-vingt-dix-neuf"

• 80 : 4 * 20 = "quatre-vingts" → means 4 times 20 so 20 is plural, thus "vingts" ends with an "s". But when it is not the ending of the word, the plural form disappear:
• 82 = 4 * 4 +2 = "quatre-vingt-deux", without an "s" at "vingt".

For some unknown reasons, 71 use an "-et-", 81 and 91 use a dash.

• 71 = 60 + 11 = "soixante-et-onze"
• 81 = 4 * 20 + 1 = "quatre-vingt-un"
• 91 = 4 * 20 + 11 = "quatre-vingt-onze"

One hundred is "cent". One thousand is "mille".

The rule is joining this and the rest with a dash:

• 130 = 100 + 30 = "cent-trente"
• 1110 = 1000 + 100 + 10 = "mille-cent-dix"

When multiplied, "cent" takes the plural mark, 's', but loses it when followed by another numeral adjective. However, the numeral adjective 'mille' is invariable, so it never takes the plural mark 's'.

• 200 = 2 * 100 = "deux-cents"
• 252 = 2 * 100 + 52 = "deux-cent-cinquante-deux"
• 2045 = 2 * 1000 + 45 = "deux-mille-quarante-cinq"
• 3 000 = 3 * 1000 = "trois-mille"
• 200 000 = 2 * 100 * 1000 = "deux-cent-mille", without a 's' in "cents"
• 180 000 = (100 + 4 * 20) * 1000 = "cent-quatre-vingt-mille", without a 's' in "vingt"

• 0: zéro
• 1: un
• 5: cinq
• 10: dix
• 11: onze
• 15: quinze
• 17: dix-sept
• 20: vingt
• 21: vingt-et-un
• 30: trente
• 35: trente-cinq
• 50: cinquante
• 51: cinquante-et-un
• 68: soixante-huit
• 70: soixante-dix
• 71: soixante-et-onze
• 74: soixante-quatorze
• 75: soixante-quinze
• 77: soixante-dix-sept
• 80: quatre-vingts
• 81: quatre-vingt-un
• 82: quatre-vingt-deux
• 91: quatre-vingt-onze
• 99: quatre-vingt-dix-neuf
• 100: cent
• 101: cent-et-un
• 105: cent-cinq
• 111: cent-onze
• 123: cent-vingt-trois
• 130: cent-trente
• 168: cent-soixante-huit
• 171: cent-soixante-et-onze
• 175: cent-soixante-quinze
• 199: cent-quatre-vingt-dix-neuf
• 200: deux-cents
• 201: deux-cent-et-un
• 555: cinq-cent-cinquante-cinq
• 999: neuf-cent-quatre-vingt-dix-neuf
• 1000: mille
• 1001: mille-et-un
• 1111: mille cent-onze
• 1199: mille cent-quatre-vingt-dix-neuf
• 1234: mille deux-cent-trente-quatre
• 1999: mille neuf-cent-quatre-vingt-dix-neuf
• 2000: deux-mille
• 2001: deux-mille-et-un
• 2020: deux-mille vingt
• 2021: deux-mille vingt-et-un
• 2345: deux-mille trois-cent-quarante-cinq
• 3000: trois-mille
• 9999: neuf-mille neuf-cent-quatre-vingt-dix-neuf
• 10000: dix-mille
• 11111: onze-mille cent-onze
• 12345: douze-mille trois-cent-quarante-cinq
• 123456: cent-vingt-trois-mille quatre-cent-cinquante-six
• 200000: deux-cent-mille
• 654321: six-cent-cinquante-quatre-mille trois-cent-vingt-et-un
• 999999: neuf-cent-quatre-vingt-dix-neuf-mille neuf-cent-quatre-vingt-dix-neuf