Use Notification.requestPermission on different browser versions as per it's implementation

Question

I have a problem where a function has its implementation changed in newer browsers. I want to call the function accordingly as per the implementation.

Notification.requestPermission().then(function (permission) {...})

This was called previously like,

Notification.requestPermission(callback);

I was calling the initial way and so in older browsers it is breaking as the promise is not returned in their implementation.

Answer 1

Taking a shot at this. It seems like you need to have a function fired conditionally with a flag.

// Outer function to prevent scope pollution
(function(){
    function thingThatINeed() {}
    // Flag to keep track of whether it is called.
    var isCalled = false;
    function conditionalCall(){
       if(!isCalled) {
           // if the conditionalCall function is called more than once, the 
           // needed function will still only be called once.
           thingThatINeed();
           isCalled = true;
       }
    }
    // Call requestPermission with the deprecated form
    var promise = Notification.requestPermission(conditionalCall);

    // if a promise is returned, then use the promise.
    if(promise){
        promise.then(conditionalCall);
    }
}());