Is there a way to ensure that $watch is only triggered once?

Question

Is there a way to ensure that $watch is only triggered once?

I implemented the $watch function, but the code within it throws an error if panodatas is undefined:

scope.$watch('panodatas', function(newVal) {
   if ('isCreate' in attrs) {
      $('.modal #points').hide()
      $('.modal #points-info').hide()
   }

   if (newVal || 'isCreate' in attrs) {
      scope.x = 0
      scope.y = 0
      scope.points = []

The challenge lies in the fact that the code executes every time panodatas changes.

Is there a way to ensure that $watch only triggers once and not on subsequent changes to panodatas?

javascript angularjs

Answer 1

Answer №1

When using <code>scope.$watch, it returns a deregistration function.

You can use this deregistration function like so:
var unregister = scope.$watch('panodatas', function(newVal) {
    unregister();
});

This means that the watch will be removed as soon as it is activated.

Answer 2

When using <code>scope.$watch, it returns a deregistration function.

You can use this deregistration function like so:
var unregister = scope.$watch('panodatas', function(newVal) {
    unregister();
});

This means that the watch will be removed as soon as it is activated.

Answer 3

Answer №2

Give this a try:

const stopWatching = $scope.$watch('someVar', () => {
   stopWatching();
});

Answer 4

Give this a try:

const stopWatching = $scope.$watch('someVar', () => {
   stopWatching();
});

Answer 5

Answer №3

To remove the $watch in the function, you can do the following -

var watcher = $scope.$watch("dates", function () {
    // ...
    watcher(); // This will clear the watch
});

This will trigger the watcher once and then clear it.

Answer 6

To remove the $watch in the function, you can do the following -

var watcher = $scope.$watch("dates", function () {
    // ...
    watcher(); // This will clear the watch
});

This will trigger the watcher once and then clear it.

Is there a way to ensure that $watch is only triggered once?

Answer №1

Answer №2

Answer №3

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