diff --git a/src/app/shared/sass-helper/css-variable.service.ts b/src/app/shared/sass-helper/css-variable.service.ts index 0190a05036f..f5911737a0a 100644 --- a/src/app/shared/sass-helper/css-variable.service.ts +++ b/src/app/shared/sass-helper/css-variable.service.ts @@ -26,6 +26,17 @@ export class CSSVariableService { return styleSheet.href.indexOf(window.location.origin) === 0; }; + /** + * Checks whether the specific stylesheet object has the property cssRules + * @param styleSheet The stylesheet + */ + hasCssRules = (styleSheet) => { + // Injected styles might have no css rules value + return styleSheet.hasOwnProperty('cssRules') && styleSheet.cssRules; + }; + + + /* Determine if the given rule is a CSSStyleRule See: https://developer.mozilla.org/en-US/docs/Web/API/CSSRule#Type_constants @@ -93,8 +104,10 @@ export class CSSVariableService { if (isNotEmpty(document.styleSheets)) { // styleSheets is array-like, so we convert it to an array. // Filter out any stylesheets not on this domain + // Filter out any stylesheets that have no cssRules property return [...document.styleSheets] .filter(this.isSameDomain) + .filter(this.hasCssRules) .reduce( (finalArr, sheet) => finalArr.concat(