如何編寫自定義的回調函數的js

Question

我想獲取回調後，消息設置爲我的回調讀取文件是這樣的：

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"); 
      } 
     } 
    ); 
} 

但控制檯沒有登錄我的回調的消息！哪裏有問題？這是做這件事的正確方法嗎？

編輯：

這個代碼工作正常，並正確

Answer 1

嘗試將其傳遞時fileReadHandler這樣除去callback函數名稱：

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

使用此代碼：

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. 檢查控制檯對象，因爲eq。只有在控制檯窗口打開的情況下才提供IE控制檯對象
2. 使用完整路徑window.console。