json数据转换字符串函数

// json to string
function jsonToString (obj){  
    var THIS = this;   
    switch(typeof(obj)){  
        case 'string':  
            return '"' + obj.replace(/(["\])/g, '\$1') + '"';  
        case 'array':  
            return '[' + obj.map(THIS.jsonToString).join(',') + ']';  
        case 'object':  
             if(obj instanceof Array){  
                var strArr = [];  
                var len = obj.length;  
                for(var i = 0; i < len; i++){  
                    strArr.push(THIS.jsonToString(obj[i]));  
                }  
                return '[' + strArr.join(',') + ']';  
            }else if(obj == null){  
                return 'null';  

            }else{  
                var string = [];  
                for (var property in obj) string.push(THIS.jsonToString(property) + ':' + THIS.jsonToString(obj[property]));  
                return '{' + string.join(',') + '}';  
            }  
        case 'number':  
            return obj;  
        case false:  
            return obj;  
    }  
}