"sitecore": {
               "context": {
                   "pageEditing": false,
                   "user": {
                       "domain": "sitecore",
                       "name": "admin"
                   },
                   "site": {
                       "name": "JssReactWeb"
                   },
                   "pageState": "normal",
                   "language": "en",
                   "languageSwitch": {
                       "de": "http:u002Fu002Fmywebu002Fdemeineseite",
                       "en": "http:u002Fu002Fmywebu002Fenmypage"
                   },

               },

const proxyOptions = {
  appRoot: __dirname,
  ...,
  customizeContext: (context, route, currentManifest, request, response) => {
    context.languageSwitch = { ... }
  },
};