javascript - Node : TypeError: callback is not a function

Question

我写了下面的代码来读取一个 xml 并返回一个 hashmap:

this.xmlObjectRepositoryLoader = function (xmlPath, callback){
        var map = {}
        var innerMap = {};
        var el;
        fs.readFile(xmlPath, "utf-8",function(err, data) {
            if(err){
                console.log('File not found!!')
            }
            else{
                console.log(data)
                var doc = domparser.parseFromString(data,"text/xml");
                var els = doc.getElementsByTagName("Child");
                for(var i =0 ; i< els .length;i++){
                    var e = elements[i];
                    eName = e.getAttribute("a");
                    var params = elm.getElementsByTagName("abc");
                    innerMap = {};
                    for(var j =0 ; j< params.length;j++){
                        var param = params[j];
                        var b = param.getAttribute("b");
                        var c= param.getAttribute("c");
                        innerMap[b] = c;
                    }
                    map[el] = innerMap;
                    innerMap={};
                };
            }
            console.log(map);
            return callback(map);
        });        
    };

我从下面的方法调用 xmlObjectRepositoryLoader 但它返回错误 TypeError: callback is not a function:

this.objectLoader = function(filePath){
        if (filePath.includes(".xml")) {
            console.log(this.xmlObjectRepositoryLoader(filePath));
    }

你能告诉我我错在哪里吗，我该如何解决

Answer 1

你正在尝试调用 callback，在这里:

return callback(map);

但是，您没有将回调传递给 xmlObjectRepositoryLoader:

console.log(this.xmlObjectRepositoryLoader(filePath));

改为这样做:

this.xmlObjectRepositoryLoader(filePath, function(map){ 
    console.log(map)
});