Node.js全局变量可访问性

Question

I am trying to write a NodeJS based application for which I declare a global variable and try to modify it in one of the functions in my code. But it does not get modified. The code looks something like this:

var num=0, check = true;
function( a, b){
  var parts = a.split("/");
  while (num == 0){
    check=false;
    fileSystem.readFile(parts[parts.length-1], function (err, fileData) {  .
    .
    check= true
    }
 }
 if(check == true){
   num++;
   console.log("check: "+check+"num"+num);
 }
}

I see value of num as 0 always. I also tried to use global.num inside the function but it dint work. Please help. Thanks in advance.

Answer 1

您的函数尚未被调用，因此没有理由更改num的值。

Answer 2

Even if your function were to be invoked, it contains an infinite loop (as far as I can tell, since you seem to have omitted some code in the loop). It will loop forever because it tests if num is 0, but num is only changed after the loop exits.