节点js在嵌套的fs.readFile调用中提供未定义的数据

Question

This is my first project in nodejs. I am unable to find the cause :

fs.readFile("/home/shaurya/Desktop/test.txt","utf-8", 
 function(err,filedata1){
    fs.readFile(filedata1,"utf-8",function(err,filedata2){
        console.log(filedata1);
        console.log(filedata2);
    });
});

"/home/shaurya/Desktop/test.txt" contains the location of a file as a string. I am reading this test.txt in outer readFile call and passing the file content as parameter to inner readFile.

Content of test.txt is : /home/shaurya/Desktop/Parser.hs.

I was expecting that I will get the output as a string for console.log(filedata2) call. Instead I got undefined .

Any thoughts?

Answer 1

I had a similar problem. In order to solve this you would you would need to append a .trim() method to the filedata1 . Apparently sometimes text editors put an extra space or new line character after the end of the stream. This should solve your problem.

Your new code:

fs.readFile("/home/shaurya/Desktop/test.txt","utf-8", 
 function(err,filedata1){
    fs.readFile(filedata1.trim(),"utf-8",function(err,filedata2){
        console.log(filedata1);
        console.log(filedata2);
    });
});

// Please note the .trim() after filedata1