loaderOptions(preprocessor, processUrls) {
        return Object.assign(preprocessor.pluginOptions, {
            sourceMap:
                preprocessor.type === 'sass' && processUrls
                    ? true
                    : this.context.isUsing('sourcemaps')
        });
    }
Prepare the preprocessor plugin options.

@param {Detail} preprocessor
@param {Boolean} processUrls