A vue-js supported smooth-scroll module based on a Stack Overflow answer by Manuel Otto.

smoothscroll.js

const SmoothScroll = (target, speed, smooth) => {
  if (target === document)
    target = (document.documentElement || document.body.parentNode || document.body) // cross browser support for document scrolling

  let moving = false;
  let pos = target.scrollTop;
  target.addEventListener('mousewheel', scrolled, false)
  /* target.addEventListener('DOMMouseScroll', scrolled, false) */

  function scrolled(e) {
    e.preventDefault(); // disable default scrolling
    let delta = e.delta || e.wheelDelta;
    if (delta === undefined) {
      //we are on firefox
      delta = -e.detail;
    }
    delta = Math.max(-1, Math.min(1, delta)) // cap the delta to [-1,1] for cross browser consistency

    pos += -delta * speed
    pos = Math.max(0, Math.min(pos, (target.scrollHeight - target.clientHeight) + (smooth * 2))) // limit scrolling

    if (!moving) update()
  }

  function update() {
    moving = true
    let delta = (pos - target.scrollTop) / smooth;

    delta -= 1;

    if(pos - target.scrollTop === smooth * 2)
      delta = 0;

    target.scrollTop += delta
    if (Math.abs(delta) > 0.5)
      requestFrame(update)
    else
      moving = false
  }

  var requestFrame = function() { // requestAnimationFrame cross browser
    return (
      window.requestAnimationFrame ||
      window.webkitRequestAnimationFrame ||
      window.mozRequestAnimationFrame ||
      window.oRequestAnimationFrame ||
      window.msRequestAnimationFrame ||
      function(func) {
        window.setTimeout(func, 1000 / 50);
      }
    );
  }()
}

export default SmoothScroll;

vue-example.vue

<template>
  ...
</template>

<script>
  import SmoothScroll from 'assets/js/smoothscroll';
  
  export default {
    mounted () {
      if(!window.smoothScroll){
        window.smoothScroll = SmoothScroll(document, 120, 12);
      }
    }
  }
</script>

@SamJakob not exactly sure what you mean by moving the variable outside the function or to a different scope.. My exact scenario is I have a main webpage with a bunch of components. As the main webpage loads, if smoothscroll.js isn't in use, it calls the function. Beyond that, there is a component at a point on the webpage within which I call the smoothscroll.js function to slow it down.

@joeljose24
So if you see on line 1, the function is defined as const SmoothScroll = (target, speed, smooth) => {

I'd suggest taking speed out of the function arguments, so it's const SmoothScroll = (target, smooth) => { and just defining speed as a variable outside of the function. e.g.,

// Set the initial speed.
let speed = 120;

export function setSpeed(newScrollSpeed) {
    speed = newScrollSpeed;
}

const SmoothScroll = (target, smooth) => {
// .. rest of the function from above (by not specifying speed as an argument it'll use the one defined above which
// will let us call setSpeed to change it)
}

export default SmoothScroll;

Then in the Vue example, you might call it like so:

import SmoothScroll, { setScrollSpeed } from 'assets/js/smoothscroll';

// ...

mounted () {
  if(!window.smoothScroll){
    window.smoothScroll = SmoothScroll(document, 12);
  }
}

// ...

Then, when you want to change the scroll speed like so:

setScrollSpeed(240);

@SamJakob hey sam, I figured a workaround for this, I'm just disabling window scroll for specific points and enabling it after a time out.
Regardless, this solution still helped me solve a bug that I had because of the scroll disabling so, thank you so much for taking the time to answer my doubt! :)