Question

js 函数中如何获取另一个函数的返回值

function getAllDeptData(){
var str = "全院";
var data = getDataByDept(str);
alert(data);
}

//获取json中的数据
function getDataByDept(obj){
var dataset = [];
$.getJSON("tourism.json",function(data){
if((obj.indexOf("全院")==0 )&& ("全院".indexOf(obj) == 0)){
$.each(data.provinces,function(i,info){
var temp = {};
temp.name = info["name"];
temp.dept = info["dept"];
temp.value = info["value"];

dataset.push(temp);
});
return dataset;
}else{
$.each(data.provinces,function(i,info){
if(info["dept"] == obj){
var temp = {};
temp.name = info["name"];
temp.dept = info["dept"];
temp.value = info["value"];

dataset.push(temp);
}
});
return dataset;
}
});
}

为什么最后打印出来的是undefined？请问我应该怎么修改呢？

Answer 1

涉及到网络通信, 你这已经是异步了

解决方案

要麽换成同步的写法

要麽使用最普通的callback写法

function getAllDeptData(){
    var str = "全院";
    getDataByDept(str,function(data)
    {
        alert(data);
    });
}

//获取json中的数据
function getDataByDept(obj,Callback){
    var dataset = [];
    $.getJSON("tourism.json",function(data){
        if((obj.indexOf("全院")==0 )&& ("全院".indexOf(obj) == 0)){
            $.each(data.provinces,function(i,info){
                var temp = {};
                temp.name = info["name"];
                temp.dept = info["dept"];
                temp.value = info["value"];
                 
                dataset.push(temp);
            });
            Callback(dataset);
        }else{
            $.each(data.provinces,function(i,info){
                if(info["dept"] == obj){
                    var temp = {};
                    temp.name = info["name"];
                    temp.dept = info["dept"];
                    temp.value = info["value"];
                     
                    dataset.push(temp);
                }
            });
            Callback(dataset);
        }
    });
}