问题描述
$apply 函数可以在任何范围内运行，包括 $rootScope.
The $apply function can run on any scope, including $rootScope.
如果我在本地范围内运行它或在我的 $rootScope 上运行它，是否会产生不同的情况?
Are there cases when it makes a difference if I run it on my local scope or if I run it on my $rootScope?
我之所以这么问是因为我想创建一个辅助函数，将给定的函数包装在 $apply 中.为此，我总是需要传入一个作用域，这 A) 烦人，B) 不容易，因为我不一定有本地作用域.
I'm asking because I'd like to create a helper function that wraps a given function in an $apply. To do that I'd always need to pass in a scope, which is A) annoying and B) not easy because I don't necessarily have a local scope.
我希望始终在 $rootScope 上调用我的辅助函数 $apply，但如果这样做有一些风险，则不会.
I'd like to always have my helper function call $apply on the $rootScope, but not if there's some risk in doing that.
推荐答案
在任何作用域上运行 $apply 总是会产生 $rootscope.$digest.它可能会产生影响的唯一情况是当您将表达式作为参数提供给 $apply 时.表达式将在当前作用域(相对于 $rootScope)中计算，但之后 $rootscope.$digest 被总是调用.
Running $apply on 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 $rootscope.$digest is always called.
源代码很清楚:rootScope.js
底线:如果您不带参数调用 $apply，则没有任何区别.
Bottom line:If you call $apply with no arguments, it makes no difference.
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