mtcute/packages/i18n/src/index.ts
2022-08-29 18:53:27 +03:00

91 lines
2.3 KiB
TypeScript

import { MtArgumentError, ParsedUpdate } from '@mtcute/client'
import {
I18nValue,
MtcuteI18nAdapter,
MtcuteI18nFunction,
OtherLanguageWrap,
} from './types'
import { createI18nStringsIndex, extractLanguageFromUpdate } from './utils'
export * from './types'
export interface MtcuteI18nParameters<Strings, Input> {
/**
* Primary language which will also be used as a fallback
*/
primaryLanguage: {
/**
* Two letter language code.
*/
name: string
/**
* Strings for the language.
*/
strings: Strings
}
otherLanguages?: Record<string, OtherLanguageWrap<Strings>>
/**
* Language that will be used if no language is specified
*
* Defaults to {@link primaryLanguage}
*/
defaultLanguage?: string
/**
* Adapter that will be used to extract language from the update.
*/
adapter?: MtcuteI18nAdapter<Input>
}
export function createMtcuteI18n<Strings, Input>(
params: MtcuteI18nParameters<Strings, Input>
): MtcuteI18nFunction<Strings, Input> {
const {
primaryLanguage,
otherLanguages,
defaultLanguage = primaryLanguage.name,
adapter = extractLanguageFromUpdate as any as MtcuteI18nAdapter<Input>,
} = params
const indexes: Record<string, Record<string, I18nValue>> = {}
const fallbackIndex = (indexes[primaryLanguage.name] =
createI18nStringsIndex(primaryLanguage.strings))
if (otherLanguages) {
Object.keys(otherLanguages).forEach((lang) => {
indexes[lang] = createI18nStringsIndex(otherLanguages[lang])
})
}
if (!(defaultLanguage in indexes)) {
throw new MtArgumentError(
'defaultLanguage is not a registered language'
)
}
const tr = (
lang: Input | string | null,
key: string,
...params: any[]
) => {
if (lang === null) lang = defaultLanguage
if (typeof lang !== 'string') {
lang = adapter(lang) ?? defaultLanguage
}
const strings = indexes[lang] ?? fallbackIndex
let val = strings[key] ?? fallbackIndex[key] ?? `[missing: ${key}]`
if (typeof val === 'function') {
val = val(...params)
}
return val
}
return tr as MtcuteI18nFunction<Strings, Input>
}