javascript variable scope binding using angularjs

Question

I am using angularjs/javascript code for image Uploading but i got stuck in variable binding , can anyone help me out, here is my code.

var image_source;
$scope.uploadedFile = function(element) {
  reader.onload = function(event) {
  image_source = event.target.result;
  $scope.$apply(function($scope) {
    $scope.files = element.files;
  });
}
console.log(image_source,event.target.result, element.files[0],  "***not working here***");

I'm binding varibale named image_source within function but when i access this outside the function it always return undefined why ?

PS:- i can get this in the typescript using phatarrow operator but how to do in javascript i dont know

File operation is Async operation. You are assigning value to image_source inside onload method. It may be the reason for not working — Ved
– Ved, Commented Jun 8, 2017 at 11:49
its function-scoped, not sure why u r expecting it to be accessible outside. fat-arrow function gets the scope of the parent-block and hence it might work in es6. r u expecting block-scope in es5?? that wont work. — Plankton
– Plankton, Commented Jun 8, 2017 at 11:50

Sami Triki · Accepted Answer · 2017-06-08 11:48:32Z

-1

If your console.log statement is called before $scope.uploadedFile which is most likely to be the case, the value will not be set, I suggest you try to call the function and put your console.log statement at the end of the function, inside the block.

That's not an angular issue but more like javascript, when you declare an anonymous function it's not called immediately

let mynumber = 1
let myfunction = () => { 
    mynumber = 2
}
console.log(mynumber) // 1
myfunction()
console.log(mynumber) // 2

answered Jun 8, 2017 at 11:48

Sami Triki

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8 Comments

Pardeep Jain Over a year ago

yes i know but i have to console outside from the fuction in some case

Sami Triki Over a year ago

I'm not sure it's useful, I assume that the chunk of file that you're showing here is your controller? You just can't put your console log statement before a function sets the value and then expect it to be set

Pardeep Jain Over a year ago

so what should i do ?

Sami Triki Over a year ago

It depends on what you want to acheive, if your console.log statement is only intended for inspecting the variable's value when it's set then just put a debugger statement and check it in the browser

Pardeep Jain Over a year ago

but always console statement runs before function, so what to do in that case ?

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