koa-i18next-middleware/src/index.js

An i18next middleware for koa2 framework.

'use strict'

import * as utils from './utils'
import LD from 'koa-i18next-detector'

export var LanguageDetector = LD

export function getHandler(i18next, options = {}) {
  return async function(ctx, next) {
    let res = ctx.response
    let req = ctx.request
    let ignores = (options.ignoreRoutes instanceof Array && options.ignoreRoutes) || []
    if (ignores.some(ignore => ctx.path.includes(ignore))) {
      return await next()
    }
    let i18n = i18next.cloneInstance({ initImmediate: false })
    i18n.on('languageChanged', lng => {
      // Keep language in sync
      req.language = lng
      req.locale = lng
      req.lng = lng
      req.languages = i18next.services.languageUtils.toResolveHierarchy(lng)
    })

    let lng = req.lng
    if (!lng && i18next.services.languageDetector) {
      lng = i18next.services.languageDetector.detect(ctx)
    }

    // set request locale
    req.language = lng
    req.locale = lng
    req.lng = lng
    req.languages = i18next.services.languageUtils.toResolveHierarchy(lng)

    // trigger sync to instance - might trigger async load!
    i18n.changeLanguage(lng || i18next.options.fallbackLng[0])

    if (req.i18nextLookupName === 'path' && options.removeLngFromUrl) {
      req.url = utils.removeLngFromUrl(req.url, i18next.services.languageDetector.options.lookupFromPathIndex)
    }

    let t = i18n.t.bind(i18n)
    let exists = i18n.exists.bind(i18n)

    // assert for req
    req.i18n = i18n
    req.t = t

    // assert for res -> template
    let localsName = options.locals || 'locals'
    if (!res[localsName]) {
      res[localsName] = {}
    }

    res[localsName].t = t
    res[localsName].exists = exists
    res[localsName].i18n = i18n
    res[localsName].language = lng
    res[localsName].languageDir = i18next.dir(lng)

    if (i18next.services.languageDetector) {
      i18next.services.languageDetector.cacheUserLanguage(ctx, lng)
    }

    // load resources
    if (req.lng) {
      await i18next.loadLanguages(req.lng)
    }
    await next()
  }
}

export default {
  getHandler
}