t.ts

import { z } from 'zod';

type SupportedLocales = 'en-US' | 'pt-BR';

export const dictionaries: Record<
  SupportedLocales,
  Record<string, Record<string, string>>
> = {
  'en-US': {
    common: {
      hello: 'Awesome!',
      hi: 'Hello {{name}} {{age}}!',
      bye: 'Goodbye {{name}}!',
      how: 'blablabla',
      banana: 'blablabla',
    },
  },
  'pt-BR': {
    common: {
      hello: 'mundo',
      hi: 'Ola {{name}} {{age}}!',
      bye: 'Tchau {{name}}!',
      how: 'xablau {{other}}',
      banana: 'goiaba e {{bananinha}}',
    },
  },
};

let currentLocale: SupportedLocales = 'en-US';

export const initialTranslation = async (
  locale: SupportedLocales = 'en-US'
) => {
  await new Promise((resolve) => {
    currentLocale = locale ?? currentLocale;
    resolve(true);
  });
};

const TranslationSchema = z.discriminatedUnion('key', [
  z.object({
    key: z.literal('common:hello'),
  }),
  z.object({
    key: z.literal('common:hi'),
    params: z.object({ name: z.string(), age: z.string() }),
  }),
  z.object({
    key: z.literal('common:bye'),
    params: z.object({ name: z.string() }),
  }),
  z.object({
    key: z.literal('common:how'),
    params: z.object({ other: z.string() }),
  }),
  z.object({
    key: z.literal('common:banana'),
    params: z.object({ bananinha: z.string() }),
  }),
]);

export const t = (
  key: z.infer<typeof TranslationSchema>,
  locale: SupportedLocales = currentLocale
) => {
  const [namespace, innerKey] = key.key.split(':');

  const sentence = dictionaries[locale][namespace][innerKey];

  let result = '';

  if ('params' in key) {
    Object.entries(key.params).forEach(([paramKey, paramValue]) => {
      result = sentence.replace(`{{${paramKey}}}`, paramValue);
    });

    return result;
  }

  return sentence;
};

t({ key: 'common:hi', params: { name: 'John', age: '20' } }, 'pt-BR'); // Hello John 20!
t({ key: 'common:banana', params: { bananinha: 'banana' } }); // goiaba e banana
t({ key: 'common:hello' }); // Awesome!

TODO:

• JSX components interpolation
• Nested keys
• Split namespaces into dedicated files (avoid merge conflicts)
• Auto-generate Zod types based on RootDictionary
• Secondary dictionaries implement RootDictionary contract