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JavaScript AngularJS Basics (1.x) Services in Angular Using Services To Save and Delete Data

Posted by kelvin atawura
kelvin atawura
Courses Plus Student 580 Points

dataService.getTodos() call

After watching the view l was sort of wondering a view thing. why was the service not called in this way 

$scope.todos = dataService.getTodos(function(res) {
            console.log(res.data);
            $scope.todos = res.data;
        });

However was called in this way instead 

dataService.getTodos(function(res) {
            console.log(res.data);
            $scope.todos = res.data;
        });

Both seems to do the same job and first one makes so much more sense to me. What's the pros and cons of using either of these?

Thomas Nilsen
Thomas Nilsen
14,957 Points
Thomas Nilsen
Thomas Nilsen
14,957 Points

Alright - Let's talk about the first example

$scope.todos = dataService.getTodos(function(res) {
            console.log(res.data);
            $scope.todos = res.data;
        });

The only reason this works is because you write $scope.todos = res.data; inside the callback function as well.

If you were to write it like this:

$scope.todos = dataService.getTodos(function(res) {
            console.log(res.data);
        });

It wouldn't work.

This function is asynchronous - meaning you won't get back a value right away. You have to get it inside the callback function.

This is an important aspect of javascript.

I would recommend reading this