Loop increment to limit the loop before passing the function

Question

I have code to copy files contained in an array for each source and destination directory in the array dirs. Each iteration through the loop calls a function that copies. It looks like this:

var filesInEachDir ["file1", "file2", "file3"];
var dirs = [
  {"source": "sourceDirectory1", "dest":"destinationDirectory1"},
  {"source": "sourceDirectory2", "dest":"destinationDirectory2"},
  {"source": "sourceDirectory3" "dest":"destinationDirectory3"},
];

for (var i = 0; i < dirs.length; i++){
  fs.mkdir(dirs[i], function(err){
    if(err){
      console.log(err);
    }else{
      copyFiles(dirs[i], filesInEachDir);
    }
   });
}

function copyFiles(dirs, files){
  for (var c = 0; c < files.length; c++){
    fs.copy(files[c], dirs.source, dirs.dest, {replace: false}, function(err){
      if (err){
        console.log(err);
      }else{
        console.log('file copied');
      }
    });
  }
}

For some reason, only files from the last item are copied dirs. If I add another item to dirs, its files will be copied, not others. So it looks like it is ifully incremented before the function is called copyFiles. Why is this happening? How can I give copyFileseach increment value i?

Answer 1

, for : , , , , - , , .

.forEach , .

var filesInEachDir = ["file1", "file2", "file3"];
var dirs = [
  {"source": "sourceDirectory1", "dest":"destinationDirectory1"},
  {"source": "sourceDirectory2", "dest":"destinationDirectory2"},
  {"source": "sourceDirectory3", "dest":"destinationDirectory3"}
];

dirs.forEach(function (dir) {
  fs.mkdir(dir, function(err) {
    if (err) {
      console.log(err);
    } else {
      copyFiles(dir, filesInEachDir);
    }
  });
});

function copyFiles(dir, files) {
  files.forEach(function (file) {
    fs.copy(file, dir.source, dir.dest, {replace: false}, function(err) {
      if (err) {
        console.log(err);
      } else {
        console.log('file copied');
      }
    });
  });
}

---

. i , mkdir. i , for. .

IIFE, i , :

for (var i = 0; i < dirs.length; i++){
  fs.mkdir(dir, (function (i) {
    return function(err) {
      if (err) {
        console.log(err);
      } else {
        copyFiles(dirs[i], filesInEachDir);
      }
    };
  })(i));
}

for (var i = 0; i < dirs.length; i++){
  fs.mkdir(dir, (function (dir) {
    return function(err) {
      if (err) {
        console.log(err);
      } else {
        copyFiles(dir, filesInEachDir);
      }
    };
  })(dirs[i]));
}

... .forEach, .