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0.14.0 • Public • Published


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A small, yet powerful, JavaScript library for converting both polytonic and monotonic Greek from/into many representations.


  1. Usage
    1. With a package manager (recommended)
    2. The old way
  2. Core functions
    1. Summary
    2. Conversion presets
    3. Conversion options
    4. Examples
  3. OOP style
    1. Summary
    2. Example
  4. Helper functions
  5. Limitations
  6. License


With a package manager (recommended)

In order to use this library in your project, simply type:

npm install greek-conversion

Import the library's functions as needed:

// ES6 modules syntax
import { KeyType, toTransliteration } from 'greek-conversion'

// CommonJS syntax
const gc = require('greek-conversion')

Then use them:

// Let's transliterate some Thucydides

  'Ἕλλησιν ἐγένετο καὶ μέρει τινὶ τῶν βαρβάρων, ' +  // Hellēsin egeneto kai
  'ὡς δὲ εἰπεῖν καὶ ἐπὶ πλεῖστον ἀνθρώπων.',         // merei tini tōn barbarōn,
  KeyType.GREEK,                                     // hōs de eipein kai epi
  { removeDiacritics: true }                         // pleiston anthrōpōn.

The old way

This is primarily intended for the use of the library in the browser in the absence of a modern development environment.

You can either import the library from the unpkg CDN ( or download the latest release on Github then include greekConversion.min.js into your project (but you could experience a CORS issue in this case and need to use a local server to run your project).

As the library is built as a module, the <script> tag needs to be set as type="module" (which is supported by all modern browsers).

You can then call the library's functions as exemplified below:

<script type="module">
  import { KeyType, toGreek } from '' // or './greekConversion.min.js'
  console.log(toGreek('anthrōpos', KeyType.TRANSLITERATION)) // ανθρωπος

Core functions


This library provides three main functions to convert a greek string: toBetaCode, toGreek & toTransliteration. You can refer to the conversion chart for further information about the expected input & output.

Functions signature is consistently:

str: string,
fromType: KeyType,
settings: Preset | MixedPreset | IConversionOptions = {}

fromType can be set to BETA_CODE | TLG_BETA_CODE | GREEK | TRANSLITERATION (e.g. KeyType.GREEK).

settings can be filled with:

  1. a Preset;
  2. a user-defined IConversionOptions object;
  3. a preset mixed with user-defined conversion options ([Preset, IConversionOptions]).

Conversion presets

The available presets are:

  1. For beta code:
Preset Description
SIMPLE_BC A simplified beta code style for faster writing
TLG Thesaurus Linguae Graecae
  1. For transliteration:
Preset Description Scope
ALA_LC American Library Association – Library of Congress Ancient and Medieval Greek (before 1454)
ALA_LC_MODERN Alternative form of the preceding Modern Greek (after 1453)
BNF_ADAPTED Bibliothèque nationale de France (adapted) Ancient Greek
ISO ISO 843 (1997) type 1 (transliteration) Ancient and Modern Greek
SBL Society of Biblical Literature Ancient Greek

Conversion options

The IConversionOptions interface provides the following controls over the conversion process:

removeDiacritics?: boolean,          // remove diacritics, except those that represent letters

removeExtraWhitespace?: boolean,     // remove potential extra whitespace

betaCodeStyle?: {
  skipSanitization?: boolean,        // prevent the deletion of non-beta code characters
  useTLGStyle?: boolean              // use the Thesaurus Linguae Graecae style. e.g. 'Ἄϊδι' → '*)/AI+DI'

greekStyle?: {
  useBetaVariant?: boolean,          // use the typographic variant 'ϐ' [U+03D0] within a word
  useGreekQuestionMark?: boolean,    // use greek question marks ';' [U+037E] rather than regular semicolons
  useLunateSigma?: boolean,          // use lunate sigmas 'ϲ, Ϲ' rather than regular sigmas
  useMonotonicOrthography?: boolean  // only output monotonic accents (tonos, diaeresis)

transliterationStyle?: {
  setCoronisStyle?: Coronis,         // set Coronis enum to PSILI | APOSTOPHE | NO (defaults to: PSILI)
  useCxOverMacron?: boolean,         // use a circumflex rather than a macron for eta, omega, etc
  beta_v?: boolean,                  // transliterate 'β' as 'v' (defaults to: 'b')
  gammaNasal_n?: boolean,            // transliterate 'γ' as 'n' when nasalization occurs
  eta_i?: boolean,                   // transliterate 'η' as 'ī' (defaults to: 'ē')
  muPi_b?: boolean,                  // transliterate 'μπ' as 'b' at the beginning of a word
  nuTau_d?: boolean,                 // transliterate 'ντ' as 'd̲' at the beginning of a word
  xi_ks?: boolean,                   // transliterate 'ξ' as 'ks' (defaults to: 'x')
  rho_rh?: boolean,                  // transliterate 'ρ' as 'rh' even if it doesn't have a rough breathing
  phi_f?: boolean,                   // transliterate 'φ' as 'f' (defaults to: 'ph')
  chi_kh?: boolean,                  // transliterate 'χ' as 'kh' (defaults to: 'ch')
  upsilon_y?: boolean,               // transliterate 'υ' as 'y' (defaults to: 'u')
  lunatesigma_s?: boolean            // transliterate 'ϲ' [U+03F2] as 's' (defaults to: 'c')

additionalChars?:                    // extend the default mapping with additional chars
 AdditionalChar[] | AdditionalChar   //   (use AdditionalChar.ALL to enable the whole set)

A more detailed description of these conversion options is available on this page.


Basic examples

toBetaCode('ανθρωπος', KeyType.GREEK) // anqrwpos
toGreek('A)/i+da', KeyType.BETA_CODE) // Ἄϊδα
toGreek('*)/AI+DA', KeyType.TLG_BETA_CODE) // Ἄϊδα
toTransliteration('ἄϋλος', KeyType.GREEK, { removeDiacritics: true }) // aulos

Using presets

toTransliteration('Φίληβος ἢ Περὶ ἡδονῆς', KeyType.GREEK, Preset.ISO) // Fílīvos ī̀ Perì hīdonī̃s
toTransliteration('Φίληβος ἢ Περὶ ἡδονῆς', KeyType.GREEK, Preset.ALA_LC) // Philēbos ē Peri hēdonēs

Using a mixed preset

toTransliteration('Φίληβος ἢ Περὶ ἡδονῆς', KeyType.GREEK, [
  { removeDiacritics: false }
]) // Phílēbos ḕ Perì hēdonē̃s

Using customized greek

const style = {
  greekStyle: {
    useLunateSigma: true


Using customized transliteration

const style = {
  transliterationStyle: {
    useCxOverMacron: true,
    chi_kh: true

toTransliteration('τέχνη', KeyType.GREEK) // téchnē
toTransliteration('τέχνη', KeyType.GREEK, style) // tékhnê

Self-conversion (reflect settings)

toBetaCode('O(pli/ths', KeyType.BETA_CODE, Preset.TLG) // *(OPLI/THS
toBetaCode('*(OPLI/THS', KeyType.TLG_BETA_CODE) // O(pli/ths

const grStyle = { greekStyle: { useLunateSigma: true } }
toGreek('ἅγιος', KeyType.GREEK, grStyle) // ἅγιοϲ

const trStyle = { transliterationStyle: { lunatesigma_s: true } }
toTransliteration('Cōkrátēc', KeyType.TRANSLITERATION, trStyle) // Sōkrátēs

OOP style


You can use the GreekString object if you want to manage several representations of a greek string. Conversions are made only as necessary.

GreekString constructor is:

str: string,
fromType: KeyType,
settings?: Preset | MixedPreset | IConversionOptions

You can access each representation by calling the following properties: betaCode, greek & transliteration.

Note that settings is also applied to the input string in order to have truly equivalent representations. You can retrieve the original string using the source property.


import { GreekString, KeyType } from 'greek-conversion'

const person = new GreekString(
  { removeDiacritics: true }

person.betaCode // anqrwpos
person.greek // ανθρωπος
person.transliteration // anthrōpos

person.source // ἄνθρωπος

Helper functions

applyGreekVariants (greekStr: string, options?: IGreekStyle): string

Applies beta/sigma variants and transforms πσ into ψ.

This function evaluates booleans useBetaVariant & useLunateSigma provided by the IGreekStyle interface.

removeDiacritics (str: string, type: KeyType): string

Removes all the diacritics from a given string. The set of diacritical marks depends of the greek string representation.

removeGreekVariants (greekStr: string, removeLunateSigma?: boolean): string

Removes beta and sigma variants.


This is what you should know before using this library:


Copyright (C) 2021, 2022, 2023, 2024 Antoine Boquet

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see

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