Typescript payload not inferred in "new i18n"

Unless I’m missing something, new i18n(config) does not infer the type of Params from config so @sveltekit-i18n/parser-default needs to be imported just to get the Parser type to declare it explicitly.

For translations.ts I am forced to do this so that my type checking doesn’t return an error:

import i18n from 'sveltekit-i18n';
import type { Config } from 'sveltekit-i18n';
import type { Parser } from '@sveltekit-i18n/parser-default';

export const defaultLocale = 'en';

export interface Payload extends Parser.PayloadDefault {
    placeholder?: string;
}

const config: Config<Payload> = {
   ...
};

export const { t, locale, locales, loading, loadTranslations, translations } = new i18n<
    Parser.Params<Payload>
>(config);

If I don’t include <Parser.Params<Payload>>, I get an error that placeholder doesn’t exist when passing it to a $t(...).

[jarda-svoboda]

It works here, when @sveltekit-i18n/base and @sveltekit-i18n/parser-default are used separately, but it does not work under sveltekit-i18n, so you are 100% right about sveltekit-i18n declaration…

[ikoruk]

I am not an expert in typescript but for example instead of:

declare class I18n<Params extends Parser.Params> extends Base<Params> {
    constructor(config?: Config);
    loadConfig: (config: Config) => Promise<void>;
}

This works for me:

declare class I18n<Params extends Parser.Params<P, M>, P = Parser.PayloadDefault, M = Modifier.DefaultProps> extends Base<Params> {
    constructor(config?: Config<P, M>);
    loadConfig: (config: Config<P, M>) => Promise<void>;
}

That way it just needs const config: Config<{param?: number}> and nothing else.