How to build a multilingual website in Next.js #2

getInitialLocale.ts

// translations/getInitialLocale.ts

import { defaultLocale } from './config'
import { Locale, isLocale } from './types'

export function getInitialLocale(): Locale {
  // preference from the previous session
  const localSetting = localStorage.getItem('locale')
  if (localSetting && isLocale(localSetting)) {
    return localSetting
  }

  // the language setting of the browser
  const [browserSetting] = navigator.language.split('-')
  if (isLocale(browserSetting)) {
    return browserSetting
  }

  return defaultLocale
}