Running $apply on $rootScope vs any other scope
The $apply function can run on any scope, including $rootScope.
Are there cases when it makes a difference if I run it on my local scope or
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Running $digest/$apply on any given scope will visit all other scopes using depth-first traversal:
https://github.com/angular/angular.js/blob/3967f5f7d6c8aa7b41a5352b12f457e2fbaa251a/src/ng/rootScope.js#L550-L558
That means that the only difference is that the $digest will start at whatever $scope it was called on
讨论(0) -
Running
$applyon any scope always results in a$rootscope.$digest. The only case where it might make a difference is when you provide an expression as an argument to$apply. The expression will be evaluated in the current scope (vs. $rootScope), but afterwards$rootscope.$digestis always called.The source code is quite clear: rootScope.js
Bottom line: If you call
$applywith no arguments, it makes no difference.讨论(0) -
/* What happens with $apply */ angular.module('myApp',[]).controller('MessageController', function($scope) { $scope.getMessage = function() { setTimeout(function() { $scope.$apply(function() { //wrapped this within $apply $scope.message = 'Fetched after 3 seconds'; console.log('message:' + $scope.message); }); }, 2000); } $scope.getMessage(); });<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.7.5/angular.min.js"></script> <body ng-app="myApp"> <div ng-controller="MessageController"> Delayed Message: {{message}} </div> </body>讨论(0) -
Another reason for running
$applyon the$rootScopeinstead of$scopetypically comes for me when I need to call$applyin a service which will be used by different controllers and therefore different scopes.
In this cases I prefer to inject the$rootScopeto the service and call $apply on it without worrying on which scopes the service will be used in the future.讨论(0)
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