如何编写自定义的回调函数的js

Question

我想获取回调后，消息设置为我的回调读取文件是这样的：

exp.getServerHandler=function (request,response){ 

    if(request.url.startsWith("/static/")){ 
     //passing my custom callback function as an input param 
     fileReadHandler(request,response,function callback(message){ 
      console.log(message); 
     }); 
    } 
}; 

function fileReadHandler(request,response,callback){ 
    fs.readFile(request.url.substr(1), 
     function(err,data) { 
      if(err){ 
       response.end("bad request"); 
       response.statusCode=400; 
       //here i want to set message as my callback param 
       callback("failed"); 
      }else{ 
       response.end(data); 
       //here i want to set message as my callback param 
       callback("successful"); 
      } 
     } 
    ); 
} 

但控制台没有登录我的回调的消息！哪里有问题？这是做这件事的正确方法吗？

编辑：

这个代码工作正常，并正确

Answer 1

尝试将其传递时fileReadHandler这样除去callback函数名称：

exp.getServerHandler=function (request,response){ 

    if(request.url.startsWith("/static/")){ 
     //passing my custom callback function as an input param 
     fileReadHandler(request,response,function(message){ 
      console.log(message); 
     }); 
    } 
}; 

function fileReadHandler(request,response,callback){ 
    fs.readFile(request.url.substr(1), 
     function(err,data) { 
      if(err){ 
       response.end("bad request"); 
       response.statusCode=400; 
       //here i want to set message as my callback param 
       callback("failed"); 
      }else{ 
       response.end(data); 
       //here i want to set message as my callback param 
       callback("successful"); 
      } 
     } 
    ); 
} 

Answer 2

使用此代码：

exp.getServerHandler=function (request,response){ 
    if(request.url.startsWith("/static/")){ 
     //passing my custom callback function as an input param 
     fileReadHandler(request,response,function callback(message){    
      if (window.console && window.console.log) 
       window.console.log(message); 
     }); 
    } 
}; 

1. 检查控制台对象，因为eq。只有在控制台窗口打开的情况下才提供IE控制台对象
2. 使用完整路径window.console。