epubjs/lib/utils/scrolltype.js

Parse and Render Epubs

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createDefiner = createDefiner;
exports.default = scrollType;

// Detect RTL scroll type
// Based on https://github.com/othree/jquery.rtl-scroll-type/blob/master/src/jquery.rtl-scroll.js
function scrollType() {
  var type = "reverse";
  var definer = createDefiner();
  document.body.appendChild(definer);

  if (definer.scrollLeft > 0) {
    type = "default";
  } else {
    if (typeof Element !== 'undefined' && Element.prototype.scrollIntoView) {
      definer.children[0].children[1].scrollIntoView();

      if (definer.scrollLeft < 0) {
        type = "negative";
      }
    } else {
      definer.scrollLeft = 1;

      if (definer.scrollLeft === 0) {
        type = "negative";
      }
    }
  }

  document.body.removeChild(definer);
  return type;
}

function createDefiner() {
  var definer = document.createElement('div');
  definer.dir = "rtl";
  definer.style.position = "fixed";
  definer.style.width = "1px";
  definer.style.height = "1px";
  definer.style.top = "0px";
  definer.style.left = "0px";
  definer.style.overflow = "hidden";
  var innerDiv = document.createElement('div');
  innerDiv.style.width = "2px";
  var spanA = document.createElement('span');
  spanA.style.width = "1px";
  spanA.style.display = "inline-block";
  var spanB = document.createElement('span');
  spanB.style.width = "1px";
  spanB.style.display = "inline-block";
  innerDiv.appendChild(spanA);
  innerDiv.appendChild(spanB);
  definer.appendChild(innerDiv);
  return definer;
}