CODEWITHSUNDEEP
javascriptangularjsthread-safety
Mik378
Mik378

Reputation: 22171

AngularJS / Is this case absolutely safe?

Just to have a confirmation.

Suppose this Javascript code using AngularJs:

            $rootScope.myNeededBoolean = false;

            $rootScope.$on('userHasJustBeenAuthenticated', function(){
                if(!$rootScope.myNeededBoolean) {
                    $rootScope.myNeededBoolean = true; 
                    //determinant assignment to myNeededBoolean so that the following
                    //piece of code will be executed once and only once.
                    pieceOfCodeToExecuteOnlyOnce();
                }
            });

It is used to trigger a piece of code when the user is logged.

Suppose this code is triggered by two distinct codes simultaneously (using $rootScope.$broadcast for instance), focused on the same event: userHasJustBeenAuthenticated.

Javascript being mono-threaded AFAIK, can I assert that $rootScope.$on will be accessed twice SEQUENTIALLY in 100% of cases?

Indeed, I want the $rootScope.myNeededBoolean to be determinant so that pieceOfCodeToExecuteOnlyOnce is executed just once.

Upvotes: 0

Views: 337

Answers (1)

Neo
Neo

Reputation: 4760

Javascript by default does not have thread. So the code block 

 if(!$rootScope.myNeededBoolean) {
    $rootScope.myNeededBoolean = true; 
    //will execute only once
 }

will complete its execution before moving away.

Upvotes: 3

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