The Context
The context provides additional objects/params from Nuxt to Vue components and is available in special nuxt lifecycle areas like asyncData , fetch , plugins , middleware  and nuxtServerInit .
Note: "The Context" we refer to here is not to be confused with the
contextobject available inVuex Actions. The two are unrelated.
function (context) {
  // Universal keys
  const {
    app,
    store,
    route,
    params,
    query,
    env,
    isDev,
    isHMR,
    redirect,
    error,
    $config
  } = context
  // Server-side
  if (process.server) {
    const { req, res, beforeNuxtRender } = context
  }
  // Client-side
  if (process.client) {
    const { from, nuxtState } = context
  }
}
 Universal keys
These keys are available both on client-side and server-side.
app
app (NuxtAppOptions)
The root Vue instance options that includes all your plugins. For example, when using i18n, you can get access to $i18n through context.app.i18n.
store
store (Vuex Store )
Vuex Store instance. Available only if the vuex store is set.
route
route (Vue Router Route )
Vue Router route instance.
params
params (Object)
Alias of route.params.
query
query (Object)
Alias of route.query.
env
env (Object)
Environment variables set in nuxt.config.js, see env API .
isDev
isDev (Boolean)
Boolean to let you know if you're in dev mode, can be useful for caching some data in production.
isHMR
isHMR (Boolean)
Boolean to let you know if the method/middleware is called from webpack hot module replacement (true only on client-side in dev mode).
redirect
redirect (Function)
Use this method to redirect the user to another route, the status code is used on the server-side, defaults to 302. redirect([status,] path [, query]).
Examples:
redirect(302, '/login')
redirect({ name: 'slug', params: { slug: mySlug } })
redirect('https://vuejs.org')
 See the Vue Router docs more info on the Location property.
redirect or error in client-side Nuxt plugin  due to hydration errors (client content would be different from what it'd expect from the server).A valid workaround would be using window.onNuxtReady(() => { window.$nuxt.$router.push('/your-route') })error
error (Function)
Use this method to show the error page: error(params). The params should have the properties statusCode and message.
$config 
$config (Object)
The actual runtime config .
Server-side keys
These keys are available only on the server-side.
req
req (http.Request )
Request from the Node.js server. If Nuxt is used as a middleware, the request object might be different depending on the framework you're using.
Not available via nuxt generate.
Res
res (http.Response )
Response from the Node.js server. If Nuxt is used as a middleware, the res object might be different depending on the framework you're using.
Not available via nuxt generate.
beforeNuxtRender
beforeNuxtRender(fn) (Function)
Use this method to update __NUXT__ variable rendered on client-side, the fn (can be asynchronous) is called with { Components, nuxtState }, see example .
beforeSerialize
beforeSerialize(fn) (Function), available from Nuxt 2.16+
Use this method to update __NUXT__ variable rendered on client-side, the fn (must be synchronous) is called with nuxtState as argument. This method is called inside the rendered method of Vue SSR, allowing you to use it in components.
Note: this usage is advanced and mostly used for Nuxt modules.
export default {
  // Using asyncData
  asyncData({ beforeSerialize }) {
    if (process.server) {
      beforeSerialize(nuxtState => {
        nuxtState.hello = 'world'
      })
    }
  },
  // Using fetch
  fetch() {
    if (process.server) {
      this.$root.context.beforeSerialize(nuxtState => {
        nuxtState.hello = 'world'
      })
    }
  }
}
 Client-side keys
These keys are available only on client-side.
from
from (Vue Router Route )
The route navigated from.
nuxtState
nuxtState (Object)
Nuxt state, useful for plugins which use beforeNuxtRender to get the nuxt state on client-side before hydration. Available only in universal mode.
 
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