function deepCopy(source) {  
    // 声明基本数据类型  
    const basicDataTypeList = ['[object Number]', '[object String]', '[object Null]', '[object Undefined]', '[object Boolean]', '[object Symbol]']  
  
    const sourceDataType = Object.prototype.toString.call(source)  
  
    // 如果 source 的数据类型是基本数据类型，则直接返回该值  
    if (basicDataTypeList.indexOf(sourceDataType) > -1) {  
        return source  
    } else {  
        // 判断如果是对象  
        if (sourceDataType === '[object Object]') {  
            let obj = {}  
            Object.keys(source).forEach(key => {  
                obj[key] = deepCopy(source[key])  
            })  
            return obj  
        } else if (sourceDataType === '[object Array]') {  
            let arr = []  
            source.forEach(item => {  
                arr.push(deepCopy(item))  
            })  
            return arr  
        } else {  
            return eval(source.toString())  
        }  
    }  
}