Method open

src/dropkick.js:379–409

()

  // is that needed? What problem was that solving?
  // to make sure this runs in the next animation tick?
  open() {
    let dropHeight, above, below, direction, dkTop, dkBottom;
    let dk = this.data.elem;
    let dkOptsList = dk.lastChild;
    // Using MDNs suggestion for crossbrowser scrollY:
    // https://developer.mozilla.org/en-US/docs/Web/API/Window/scrollY
    let supportPageOffset = window.pageXOffset !== undefined;
    let isCSS1Compat = ((document.compatMode || "") === "CSS1Compat");
    let scrollY = supportPageOffset ? window.pageYOffset : isCSS1Compat ? document.documentElement.scrollTop : document.body.scrollTop;

    dkTop = _.offset( dk ).top - scrollY;
    dkBottom = window.innerHeight - ( dkTop + dk.offsetHeight );

    if ( this.isOpen || this.multiple ) { return false; }

    dkOptsList.style.display = "block";
    dropHeight = dkOptsList.offsetHeight;
    dkOptsList.style.display = "";

    above = dkTop > dropHeight;
    below = dkBottom > dropHeight;
    direction = above && !below ? "-up" : "-down";

    this.isOpen = true;
    _.addClass( dk, "dk-select-open" + direction );
    dkOptsList.setAttribute( "aria-expanded", "true" );
    this._scrollTo( this.options.length - 1 );
    this._scrollTo( this.selectedIndex );

    this.data.settings.open.call( this );
  }

  /**
   * Disables or enables an option; if only a boolean is passed (or nothing),