webdash-readme-preview
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Preview your README.md straight from the dashboard
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JavaScript
/**
@license
Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
*/
;
export let nativeShadow = !(window['ShadyDOM'] && window['ShadyDOM']['inUse']);
export let nativeCssVariables;
/**
* @param {(ShadyCSSOptions | ShadyCSSInterface)=} settings
*/
function calcCssVariables(settings) {
if (settings && settings['shimcssproperties']) {
nativeCssVariables = false;
} else {
// chrome 49 has semi-working css vars, check if box-shadow works
// safari 9.1 has a recalc bug: https://bugs.webkit.org/show_bug.cgi?id=155782
// However, shim css custom properties are only supported with ShadyDOM enabled,
// so fall back on native if we do not detect ShadyDOM
// Edge 15: custom properties used in ::before and ::after will also be used in the parent element
// https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/12414257/
nativeCssVariables = nativeShadow || Boolean(!navigator.userAgent.match(/AppleWebKit\/601|Edge\/15/) &&
window.CSS && CSS.supports && CSS.supports('box-shadow', '0 0 0 var(--foo)'));
}
}
if (window.ShadyCSS && window.ShadyCSS.nativeCss !== undefined) {
nativeCssVariables = window.ShadyCSS.nativeCss;
} else if (window.ShadyCSS) {
calcCssVariables(window.ShadyCSS);
// reset window variable to let ShadyCSS API take its place
window.ShadyCSS = undefined;
} else {
calcCssVariables(window['WebComponents'] && window['WebComponents']['flags']);
}