signal-desktop/ts/util/setupI18n.ts
2021-10-26 14:15:33 -05:00

84 lines
2.1 KiB
TypeScript

// Copyright 2018-2020 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import type { LocaleMessagesType } from '../types/I18N';
import type { LocalizerType } from '../types/Util';
import * as log from '../logging/log';
export function setupI18n(
locale: string,
messages: LocaleMessagesType
): LocalizerType {
if (!locale) {
throw new Error('i18n: locale parameter is required');
}
if (!messages) {
throw new Error('i18n: messages parameter is required');
}
const getMessage: LocalizerType = (key, substitutions) => {
const entry = messages[key];
if (!entry) {
log.error(
`i18n: Attempted to get translation for nonexistent key '${key}'`
);
return '';
}
if (Array.isArray(substitutions) && substitutions.length > 1) {
throw new Error(
'Array syntax is not supported with more than one placeholder'
);
}
if (
typeof substitutions === 'string' ||
typeof substitutions === 'number'
) {
throw new Error('You must provide either a map or an array');
}
const { message } = entry;
if (!substitutions) {
return message;
}
if (Array.isArray(substitutions)) {
return substitutions.reduce(
(result, substitution) => result.replace(/\$.+?\$/, substitution),
message
);
}
const FIND_REPLACEMENTS = /\$([^$]+)\$/g;
let match = FIND_REPLACEMENTS.exec(message);
let builder = '';
let lastTextIndex = 0;
while (match) {
if (lastTextIndex < match.index) {
builder += message.slice(lastTextIndex, match.index);
}
const placeholderName = match[1];
const value = substitutions[placeholderName];
if (!value) {
log.error(
`i18n: Value not provided for placeholder ${placeholderName} in key '${key}'`
);
}
builder += value || '';
lastTextIndex = FIND_REPLACEMENTS.lastIndex;
match = FIND_REPLACEMENTS.exec(message);
}
if (lastTextIndex < message.length) {
builder += message.slice(lastTextIndex);
}
return builder;
};
getMessage.getLocale = () => locale;
return getMessage;
}