Scroll の up, down を検知する

以下、vuejs syntax に従って書くと...

mounted() {

  window.addEventListener('scroll', this.wheelDelta)

},

data() {

  return {

    currentPosition: 0,

    previousPosition: 0,

    scrollDelta: 0

  }

},

methods: {

  wheelDelta() {

    this.currentPosition = document.documentElement.scrollTop

    if(this.currentPosition > this.previousPosition) {

      this.scrollDelta = 1

    } else {

      this.scrollDelta = 0

    }

    this.previousPosition = this.currentPosition

  }

 

参考:

https://stackoverflow.com/questions/4670834/capturing-the-scroll-down-event/46339008#46339008

 

https://stackoverflow.com/questions/4670834/capturing-the-scroll-down-event/46339008#46339008