text: /**
   * 类型判断
   */
  
  export function isString(obj) {
    return Object.prototype.toString.call(obj) === '[object String]';
  }
  
  export function isObject(obj) {
    return Object.prototype.toString.call(obj) === '[object Object]';
  }
  
  export function isHtmlElement(node) {
    return node && node.nodeType === Node.ELEMENT_NODE;
  }
  
  export const isFunction = (functionToCheck) => {
    var getType = {};
    return functionToCheck && getType.toString.call(functionToCheck) === '[object Function]';
  };
  
  export const isUndefined = (val) => {
    return val === void 0;
  };
  
  export const isDefined = (val) => {
    return val !== undefined && val !== null;
  };
  