set value for a global variable in local nested function

Question

I have the following function

function fileExists(FileName) {
    var retvar="false";
    window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function(fileSystem) {

      fileSystem.root.getFile(FileName, null,
           function() {
              fileEntry.file(function() {
                 alert("Exists");
              },
              function() {

       });
      },
      function () {
          retvar = "true";
          alert(retvar);  //says true
      });
     },null);

    alert(retvar);  //says false
}

here, i have to set the value of retvar as true in the inner nested function. I can't pass that value outside that function. Could any one tell me any idea for passing that value to the parent function?

Are you using "true" and "false" as Strings for a specific reason? Wouldn't it be better to use true and false directly as booleans? — Dani
– Dani, Commented Nov 19, 2013 at 10:39
what is the sequence of execution check by adding 1 more hardcoded parameter in alert... May be your outer alert is called first. — Divesh Salian
– Divesh Salian, Commented Nov 19, 2013 at 10:48
the inner alert is executing first. Just now i checked it by differentiating them by alert("inner value : " + retvar); and alert("outer value : " + retvar); the inner alert is executing first — Prabakaran Raja
– Prabakaran Raja, Commented Nov 19, 2013 at 10:58

ubuntugod · Accepted Answer · 2018-08-19 07:59:20Z

3

Oh! thanks google! for answering me!

I had to initialize the variable before the function!

The answer should be

var retvar="";
function fileExists(FileName) {
    retvar = "false";
    window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function(fileSystem) {

      fileSystem.root.getFile(FileName, null,
           function() {
              fileEntry.file(function() {
                 alert("Exists");
              },
              function() {

       });
      },
      function () {
          retvar = "true";
          alert(retvar);  //says true
      });
     },null);

    alert(retvar);  //says same if it is assigned as like in the inner loop
}

edited Aug 19, 2018 at 7:59

ubuntugod

6521 gold badge9 silver badges16 bronze badges

answered Nov 19, 2013 at 11:12

Prabakaran Raja

7202 gold badges11 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Srneczek Over a year ago

Is this only solution? Since it doesn't sound right from OOP point of view to have global variable for every single nested function which needs to return something.

Collectives™ on Stack Overflow

set value for a global variable in local nested function

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related