src/translation-service.js
/**
* @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
*/
/* globals window */
/**
* @module utils/translation-service
*/
import CKEditorError from './ckeditorerror';
/* istanbul ignore else */
if ( !window.CKEDITOR_TRANSLATIONS ) {
window.CKEDITOR_TRANSLATIONS = {};
}
/**
* Adds translations to existing ones or overrides the existing translations. These translations will later
* be available for the {@link module:utils/locale~Locale#t `t()`} function.
*
* The `translations` is an object which consists of `messageId: translation` pairs. Note that the message ID can be
* either constructed from the message string or from the message ID if it was passed
* (this happens rarely and mostly for short messages or messages with placeholders).
* Since the editor displays only the message string, the message ID can be found either in the source code or in the
* built translations for another language.
*
* add( 'pl', {
* 'Cancel': 'Anuluj',
* 'IMAGE': 'obraz', // Note that the `IMAGE` comes from the message ID, while the string can be `image`.
* } );
*
* If the message is supposed to support various plural forms, make sure to provide an array with the singular form and all plural forms:
*
* add( 'pl', {
* 'Add space': [ 'Dodaj spację', 'Dodaj %0 spacje', 'Dodaj %0 spacji' ]
* } );
*
* You should also specify the third argument (the `getPluralForm()` function) that will be used to determine the plural form if no
* language file was loaded for that language. All language files coming from CKEditor 5 sources will have this option set, so
* these plural form rules will be reused by other translations added to the registered languages. The `getPluralForm()` function
* can return either a Boolean or a number.
*
* add( 'en', {
* // ... Translations.
* }, n => n !== 1 );
* add( 'pl', {
* // ... Translations.
* }, n => n == 1 ? 0 : n % 10 >= 2 && n % 10 <= 4 && ( n % 100 < 10 || n % 100 >= 20 ) ? 1 : 2 );
*
* All translations extend the global `window.CKEDITOR_TRANSLATIONS` object. An example of this object can be found below:
*
* {
* pl: {
* dictionary: {
* 'Cancel': 'Anuluj',
* 'Add space': [ 'Dodaj spację', 'Dodaj %0 spacje', 'Dodaj %0 spacji' ]
* },
* // A function that returns the plural form index.
* getPluralForm: n => n !==1
* }
* // Other languages.
* }
*
* If you cannot import this function from this module (e.g. because you use a CKEditor 5 build), you can
* still add translations by extending the global `window.CKEDITOR_TRANSLATIONS` object by using a function like
* the one below:
*
* function addTranslations( language, translations, getPluralForm ) {
* if ( !window.CKEDITOR_TRANSLATIONS ) {
* window.CKEDITOR_TRANSLATIONS = {};
* }
* if ( !window.CKEDITOR_TRANSLATIONS[ language ] ) {
* window.CKEDITOR_TRANSLATIONS[ language ] = {};
* }
*
* const languageTranslations = window.CKEDITOR_TRANSLATIONS[ language ];
*
* languageTranslations.dictionary = languageTranslations.dictionary || {};
* languageTranslations.getPluralForm = getPluralForm || languageTranslations.getPluralForm;
*
* // Extend the dictionary for the given language.
* Object.assign( languageTranslations.dictionary, translations );
* }
*
* @param {String} language Target language.
* @param {Object.<String,*>} translations An object with translations which will be added to the dictionary.
* For each message ID the value should be either a translation or an array of translations if the message
* should support plural forms.
* @param {Function} getPluralForm A function that returns the plural form index (a number).
*/
export function add( language, translations, getPluralForm ) {
if ( !window.CKEDITOR_TRANSLATIONS[ language ] ) {
window.CKEDITOR_TRANSLATIONS[ language ] = {};
}
const languageTranslations = window.CKEDITOR_TRANSLATIONS[ language ];
languageTranslations.dictionary = languageTranslations.dictionary || {};
languageTranslations.getPluralForm = getPluralForm || languageTranslations.getPluralForm;
Object.assign( languageTranslations.dictionary, translations );
}
/**
* **Note:** This method is internal, use {@link module:utils/locale~Locale#t the `t()` function} instead to translate
* the editor UI parts.
*
* This function is responsible for translating messages to the specified language. It uses translations added perviously
* by {@link module:utils/translation-service~add} (a translations dictionary and the `getPluralForm()` function
* to provide accurate translations of plural forms).
*
* When no translation is defined in the dictionary or the dictionary does not exist, this function returns
* the original message string or the message plural depending on the number of elements.
*
* translate( 'pl', { string: 'Cancel' } ); // 'Cancel'
*
* The third optional argument is the number of elements, based on which the single form or one of the plural forms
* should be picked when the message is supposed to support various plural forms.
*
* translate( 'en', { string: 'Add a space', plural: 'Add %0 spaces' }, 1 ); // 'Add a space'
* translate( 'en', { string: 'Add a space', plural: 'Add %0 spaces' }, 3 ); // 'Add %0 spaces'
*
* The message should provide an ID using the `id` property when the message strings are not unique and their
* translations should be different.
*
* translate( 'en', { string: 'image', id: 'ADD_IMAGE' } );
* translate( 'en', { string: 'image', id: 'AN_IMAGE' } );
*
* @protected
* @param {String} language Target language.
* @param {module:utils/translation-service~Message|String} message A message that will be translated.
* @param {Number} [quantity] The number of elements for which a plural form should be picked from the target language dictionary.
* @returns {String} Translated sentence.
*/
export function _translate( language, message, quantity = 1 ) {
if ( typeof quantity !== 'number' ) {
/**
* An incorrect value was passed to the translation function. This was probably caused
* by an incorrect message interpolation of a plural form. Note that for messages supporting plural forms
* the second argument of the `t()` function should always be a number or an array with a number as the first element.
*
* @error translation-service-quantity-not-a-number
*/
throw new CKEditorError( 'translation-service-quantity-not-a-number: Expecting `quantity` to be a number.', null, { quantity } );
}
const numberOfLanguages = getNumberOfLanguages();
if ( numberOfLanguages === 1 ) {
// Override the language to the only supported one.
// This can't be done in the `Locale` class, because the translations comes after the `Locale` class initialization.
language = Object.keys( window.CKEDITOR_TRANSLATIONS )[ 0 ];
}
const messageId = message.id || message.string;
if ( numberOfLanguages === 0 || !hasTranslation( language, messageId ) ) {
if ( quantity !== 1 ) {
// Return the default plural form that was passed in the `message.plural` parameter.
return message.plural;
}
return message.string;
}
const dictionary = window.CKEDITOR_TRANSLATIONS[ language ].dictionary;
const getPluralForm = window.CKEDITOR_TRANSLATIONS[ language ].getPluralForm || ( n => n === 1 ? 0 : 1 );
if ( typeof dictionary[ messageId ] === 'string' ) {
return dictionary[ messageId ];
}
const pluralFormIndex = Number( getPluralForm( quantity ) );
// Note: The `translate` function is not responsible for replacing `%0, %1, ...` with values.
return dictionary[ messageId ][ pluralFormIndex ];
}
/**
* Clears dictionaries for test purposes.
*
* @protected
*/
export function _clear() {
window.CKEDITOR_TRANSLATIONS = {};
}
// Checks whether the dictionary exists and translation in that dictionary exists.
function hasTranslation( language, messageId ) {
return (
!!window.CKEDITOR_TRANSLATIONS[ language ] &&
!!window.CKEDITOR_TRANSLATIONS[ language ].dictionary[ messageId ]
);
}
function getNumberOfLanguages() {
return Object.keys( window.CKEDITOR_TRANSLATIONS ).length;
}
/**
* The internationalization message interface. A message that implements this interface can be passed to the `t()` function
* to be translated to the target UI language.
*
* @typedef {Object} module:utils/translation-service~Message
*
* @property {String} string The message string to translate. Acts as a default translation if the translation for a given language
* is not defined. When the message is supposed to support plural forms, the string should be the English singular form of the message.
* @property {String} [id] The message ID. If passed, the message ID is taken from this property instead of the `message.string`.
* This property is useful when various messages share the same message string, for example, the `editor` string in `in the editor`
* and `my editor` sentences.
* @property {String} [plural] The plural form of the message. This property should be skipped when a message is not supposed
* to support plural forms. Otherwise it should always be set to a string with the English plural form of the message.
*/