i18NextManager gets a requested language, and returns the t function

i18nextManager.js

const i18next = require("i18next");
i18next.init({
  lng,
  resources: {
    en: {
      translation: {
        greeting_key: "hello",
      },
    },
    es: {
      translation: {
        greeting_key: "hola",
      },
    },
  },
});