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What is $digest and $apply?

Ravi Vishwakarma 640 28-Dec-2025

What is $digest and $apply? explain with example.

angular js

Updated on 12-Feb-2026

Ravi Vishwakarma

IT-Hardware & Networking

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Richal Singh

12-Feb-2026

In AngularJS (1.x), $digest and $apply are core methods used for change detection and synchronizing the model (scope) with the view (HTML).

$digest

$digest() runs the digest cycle, where Angular checks all registered watchers and updates the DOM if model values have changed.

It processes the current scope and its child scopes.

It does not evaluate expressions globally.

Angular automatically calls $digest() during built-in events like ng-click, ng-model, $http, etc.

Example:

$scope.counter = 0;
$scope.increment = function () {
   $scope.counter++;
   $scope.$digest(); // manually triggering digest
};

Normally, you don’t call $digest() directly unless you know what you’re doing.

$apply

$apply() is used when code runs outside Angular’s context (e.g., setTimeout, third-party JS). It executes your function and then automatically triggers a $digest() cycle.

Example:

$scope.message = "Hello";
setTimeout(function () {
   $scope.$apply(function () {
       $scope.message = "Updated from setTimeout";
   });
}, 2000);

Here:

$apply() runs the function.

Then Angular internally calls $digest() to update the view.

Difference (Programming View)

$digest() → Performs change detection.

$apply() → Executes external code + triggers $digest() automatically.

In short, use $apply() when updating scope outside Angular; $digest() is the internal mechanism that updates bindings.

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What is $digest and $apply?

Ravi Vishwakarma

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1 Answers

$digest

Example:

$apply

Example:

Difference (Programming View)

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