'use strict';
/* eslint-env browser */
/** @namespace cssInjector */
/**
* @summary Insert base stylesheet into DOM
*
* @desc Creates a new `` element from the named text string(s) and inserts it but only if it does not already exist in the specified container as per `referenceElement`.
*
* > Caveat: If stylesheet is for use in a shadow DOM, you must specify a local `referenceElement`.
*
* @returns A reference to the newly created `` element.
*
* @param {string|string[]} cssRules
* @param {string} [ID]
* @param {undefined|null|Element|string} [referenceElement] - Container for insertion. Overloads:
* * `undefined` type (or omitted): injects stylesheet at top of `...` element
* * `null` value: injects stylesheet at bottom of `...` element
* * `Element` type: injects stylesheet immediately before given element, wherever it is found.
* * `string` type: injects stylesheet immediately before given first element found that matches the given css selector.
*
* @memberOf cssInjector
*/
function cssInjector(cssRules, ID, referenceElement) {
if (typeof referenceElement === 'string') {
referenceElement = document.querySelector(referenceElement);
if (!referenceElement) {
throw 'Cannot find reference element for CSS injection.';
}
} else if (referenceElement && !(referenceElement instanceof Element)) {
throw 'Given value not a reference element.';
}
var container = referenceElement && referenceElement.parentNode || document.head || document.getElementsByTagName('head')[0];
if (ID) {
ID = cssInjector.idPrefix + ID;
if (container.querySelector('#' + ID)) {
return; // stylesheet already in DOM
}
}
var style = document.createElement('style');
style.type = 'text/css';
if (ID) {
style.id = ID;
}
if (cssRules instanceof Array) {
cssRules = cssRules.join('\n');
}
cssRules = '\n' + cssRules + '\n';
if (style.styleSheet) {
style.styleSheet.cssText = cssRules;
} else {
style.appendChild(document.createTextNode(cssRules));
}
if (referenceElement === undefined) {
referenceElement = container.firstChild;
}
container.insertBefore(style, referenceElement);
return style;
}
/**
* @summary Optional prefix for `