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Nuxt Lifecycle

understanding-nuxt-2-12-lifecycle-hooks

No matter which tool you use, you will always feel more confident when you understand how the tool works under the hood. The same applies to Nuxt.js. The goal of this chapter is to give you a high-level overview of the different parts of the framework, their order of execution and how they work together.

The Nuxt.js lifecycle describes what happens after the build phase, where your application is bundled, chunked and minified. What happens after this phase depends on whether you have server-side rendering enabled or not. If you have, it furthermore depends on the type of server-side rendering you have chosen:

Dynamic SSR (nuxt start)

or Static Site Generation (nuxt generate).

Lifecycle

Server

For SSR, these steps will be executed for every initial request to your app

  • The server starts (nuxt start)

When using static site generation, the server steps are only executed on build time, but once for every page that will be generated

  • The generation process starts (nuxt generate)

  • Nuxt hooks

  • serverMiddleware

  • Server-side Nuxt plugins

    • in order as defined in nuxt.config.js
  • nuxtServerInit

    • Vuex action that is called only on server-side to pre-populate the store
    • First argument is the Vuex context, second argument is the Nuxt.js context
      • Dispatch other actions from here → only "entry point" for subsequent store actions on server-side
    • can only be defined in store/index.js
  • Middleware

    • Global middleware
    • Layout middleware
    • Route middleware
  • asyncData

  • beforeCreate (Vue lifecycle method)

  • created (Vue lifecycle method)

  • The new fetch (top to bottom, siblings = parallel)

  • Serialization of state (render:routeContext Nuxt.js hook)

  • the HTML rendering happens (render:route Nuxt.js hook)

  • render:routeDone hook when HTML has been sent to the browser

  • generate:before Nuxt.js hook

  • HTML files are generated

    • Full static generation
      • e.g. static payloads are extracted
    • generate:page (HTML editable)
    • generate:routeCreated (Route generated)
  • generate:done when all HTML files have been generated

Client

This part of the lifecycle is fully executed in the browser, no matter which Nuxt.js mode you've chosen.

  • Receives the HTML
  • Loading assets (e.g. Javascript)
  • Vue Hydration
  • Middleware
    • Global middleware
    • Layout middleware
    • Route middleware
  • asyncData (blocking)
  • client-side Nuxt.js plugin
    • in order as defined in nuxt.config.js
  • beforeCreate (Vue lifecycle method)
  • created (Vue lifecycle method)
  • The new fetch (top to bottom, siblings = parallel) (non-blocking)
  • beforeMount (Vue lifecycle method)
  • mounted (Vue lifecycle method)

Same as for the client part, everything is happening in the browser but only when navigating via <NuxtLink>. Furthermore, no page content is displayed until all blocking tasks are fulfilled.

Check out the component chapter to see more info on <NuxtLink>

  • middleware (blocking)
    • Global middleware
    • Layout middleware
    • Route middleware
  • asyncData (blocking)
  • asyncData (blocking) [or full static payload loading]
  • beforeCreate & created (Vue lifecycle methods)
  • fetch (non-blocking)
  • beforeMount & mounted

What's next

Check out the Features book