Sharkey/packages/frontend/src/scripts/i18n.ts

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/*
* SPDX-FileCopyrightText: syuilo and other misskey contributors
* SPDX-License-Identifier: AGPL-3.0-only
*/
import type { ILocale, ParameterizedString } from '../../../../locales/index.js';
type FlattenKeys<T extends ILocale, TPrediction> = keyof {
[K in keyof T as T[K] extends ILocale
? FlattenKeys<T[K], TPrediction> extends infer C extends string
? `${K & string}.${C}`
: never
: T[K] extends TPrediction
? K
: never]: T[K];
};
type ParametersOf<T extends ILocale, TKey extends FlattenKeys<T, ParameterizedString<string>>> = T extends ILocale
? TKey extends `${infer K}.${infer C}`
// @ts-expect-error -- C は明らかに FlattenKeys<T[K], ParameterizedString<string>> になるが、型システムはここでは TKey がドット区切りであることのコンテキストを持たないので、型システムに合法にて示すことはできない。
? ParametersOf<T[K], C>
: TKey extends keyof T
? T[TKey] extends ParameterizedString<infer P>
? P
: never
: never
: never;
type Ts<T extends ILocale> = {
readonly [K in keyof T as T[K] extends ParameterizedString<string> ? never : K]: T[K] extends ILocale ? Ts<T[K]> : string;
};
export class I18n<T extends ILocale> {
constructor(private locale: T) {
//#region BIND
this.t = this.t.bind(this);
//#endregion
}
public get ts(): Ts<T> {
if (_DEV_) {
class Handler<TTarget extends object> implements ProxyHandler<TTarget> {
get(target: TTarget, p: string | symbol): unknown {
const value = target[p as keyof TTarget];
if (typeof value === 'object') {
// eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- 実際には null がくることはないので。
return new Proxy(value!, new Handler<TTarget[keyof TTarget] & object>());
}
if (typeof value === 'string') {
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const parameters = Array.from(value.matchAll(/\{(\w+)\}/g), ([, parameter]) => parameter);
if (parameters.length) {
console.error(`Missing locale parameters: ${parameters.join(', ')} at ${String(p)}`);
}
return value;
}
console.error(`Unexpected locale key: ${String(p)}`);
return p;
}
}
return new Proxy(this.locale, new Handler()) as Ts<T>;
}
return this.locale as Ts<T>;
}
/**
* @deprecated 使 locale vue
*/
public t<TKey extends FlattenKeys<T, string>>(key: TKey): string;
public t<TKey extends FlattenKeys<T, ParameterizedString<string>>>(key: TKey, args: { readonly [_ in ParametersOf<T, TKey>]: string | number }): string;
public t(key: string, args?: { readonly [_: string]: string | number }) {
let str: string | ParameterizedString<string> | ILocale = this.locale;
for (const k of key.split('.')) {
str = str[k];
if (_DEV_) {
if (typeof str === 'undefined') {
console.error(`Unexpected locale key: ${key}`);
return key;
}
}
}
if (args) {
if (_DEV_) {
const missing = Array.from((str as string).matchAll(/\{(\w+)\}/g), ([, parameter]) => parameter).filter(parameter => !Object.hasOwn(args, parameter));
if (missing.length) {
console.error(`Missing locale parameters: ${missing.join(', ')} at ${key}`);
}
}
for (const [k, v] of Object.entries(args)) {
const search = `{${k}}`;
if (_DEV_) {
if (!(str as string).includes(search)) {
console.error(`Unexpected locale parameter: ${k} at ${key}`);
}
}
str = (str as string).replace(search, v.toString());
}
}
return str;
}
}