this code work for me :)


/** @odoo-module */
import publicWidget from '@web/legacy/js/public/public_widget';

publicWidget.registry.customMenuBar = publicWidget.Widget.extend({
    selector: '#wrapwrap',

    start: function () {
       this.$el.on('scroll', this._onScroll.bind(this));
       return this._super();
    },

    _onScroll: function () {
       var scrollTop = this.$el.scrollTop();
       if (scrollTop > 100) {
          console.log('More than 100px');
       } else {
          console.log('Lower than 100px');
       }
    },
})