welsonjs/node_modules/modernizr/feature-detects/css/transformstylepreserve3d.js

/*!
{
  "name": "CSS Transform Style preserve-3d",
  "property": "preserve3d",
  "authors": ["denyskoch", "aFarkas"],
  "tags": ["css"],
  "notes": [{
    "name": "MDN Docs",
    "href": "https://developer.mozilla.org/en-US/docs/Web/CSS/transform-style"
  }, {
    "name": "Related Github Issue",
    "href": "https://github.com/Modernizr/Modernizr/issues/1748"
  }]
}
!*/
/* DOC
Detects support for `transform-style: preserve-3d`, for getting a proper 3D perspective on elements.
*/
define(['Modernizr', 'createElement', 'docElement'], function(Modernizr, createElement, docElement) {
  Modernizr.addTest('preserve3d', function() {
    var outerAnchor, innerAnchor;
    var CSS = window.CSS;
    var result = false;

    if (CSS && CSS.supports && CSS.supports('(transform-style: preserve-3d)')) {
      return true;
    }

    outerAnchor = createElement('a');
    innerAnchor = createElement('a');

    outerAnchor.style.cssText = 'display: block; transform-style: preserve-3d; transform-origin: right; transform: rotateY(40deg);';
    innerAnchor.style.cssText = 'display: block; width: 9px; height: 1px; background: #000; transform-origin: right; transform: rotateY(40deg);';

    outerAnchor.appendChild(innerAnchor);
    docElement.appendChild(outerAnchor);

    result = innerAnchor.getBoundingClientRect();
    docElement.removeChild(outerAnchor);

    result = result.width && result.width < 4;
    return result;
  });
});