How to listen to scroll events in vue nuxtjs?

Using window or any other browser-specific API in created or beforeCreate will lead to problems because platform-specific APIs like document or window are not available on the server (where SSR happens). Instead, move the logic from created into beforeMount. Leaving it in created and checking it via process.browser would work as well but is not as clean and can lead to confusion easily.

export default {
  methods: {
    handleScroll () {
      // Your scroll handling here
      console.log(window.scrollY)
    }
  },
  beforeMount () {
    window.addEventListener('scroll', this.handleScroll)
  },
  beforeDestroy () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}

Only created and beforeCreate are executed on both sides, server and client. Therefore you don't need guarding ifs in beforeMount or beforeDestroy.

Further read about ssr-ready Vue components

window is undefined because nuxt JS is server side rendered.

So try it using process.client variable

methods: {
  handleScroll () {
    console.log(window.scrollY)
  }
},
created () {
    if (process.client) { 
        window.addEventListener('scroll', this.handleScroll);
    }
},
destroyed () {
    if (process.client) { 
        window.removeEventListener('scroll', this.handleScroll);
    }
}

See link for more info