['viewBox', 'fill', 'stroke', 'stroke-linecap', 'stroke-linejoin'].forEach(prop => {
                    if (options.config.props.hasOwnProperty(prop) && typeof (options.config.props[prop]) !== 'string') {
                        error.type = `options.config.props.${prop}`;
                        error.message = `Config ${prop} property is not a string.`;