$ rootScope。$广播与$范围。$放出 [英] $rootScope.$broadcast vs. $scope.$emit

问题描述

现在 $广播之间的性能差异和 $发出已经被淘汰了，没有任何理由为preFER $范围。$发出到 $ rootScope。$广播？

Now that the performance difference between $broadcast and $emit has been eliminated, is there any reason to prefer $scope.$emit to $rootScope.$broadcast?

他们是不同的，是的。

They are different, yes.

$发出被限制的范围层次结构（向上） - 这可能是好的，如果它符合你的设计，但在我看来，一个相当任意的限制

$emit is restricted to the scope hierarchy (upwards) - this may be good, if it fits your design, but it seems to me a rather arbitrary restriction.

$ rootScope。$广播可以跨所有的选择的听的事件，这是在我的脑海一个更明智的限制。

$rootScope.$broadcast works across all that choose to listen to the event, which is a more sensible restriction in my mind.

我缺少的东西吗？

编辑：

要响应于一个答案澄清，调度的方向不我后的问题。 $ $范围发出向上调度该事件，而 $ $范围广播 - 向下。但是，为什么不总是使用 $ rootScope。$广播来达到所有预期的听众？

To clarify in response to an answer, the direction of the dispatch is not the issue I'm after. $scope.$emit dispatches the event upwards, and $scope.$broadcast - downwards. But why not always use $rootScope.$broadcast to reach all the intended listeners?

推荐答案

$ rootScope。$发出只能让其他 $ rootScope 听众抓住它。这是一件好事，当你不希望每个 $范围来得到它。大多是高层次的沟通。可以把它当作成年人在一个房间里互相交谈，让孩子们可以不听。

$rootScope.$emit only lets other $rootScope listeners catch it. This is good when you don't want every $scope to get it. Mostly a high level communication. Think of it as adults talking to each other in a room so the kids can't hear them.

$ rootScope。$广播是让pretty所有事情听到它的方法。这将是父母相当于大呼小叫，晚餐准备好所以大家在家里听到它。

$rootScope.$broadcast is a method that lets pretty much everything hear it. This would be the equivalent of parents yelling that dinner is ready so everyone in the house hears it.

$范围。$发出是当你想要的 $范围及其所有的父母和 $ rootScope 听到该事件。这是一个孩子在家里抱怨他们的父母（但不是在一家杂货店，而其他的孩子能听到）。

$scope.$emit is when you want that $scope and all its parents and $rootScope to hear the event. This is a child whining to their parents at home (but not at a grocery store where other kids can hear).

$范围。$广播是 $范围本身和它的孩子。这是一个孩子窃窃私语的动物标本让他们的父母就听不到了。

$scope.$broadcast is for the $scope itself and its children. This is a child whispering to its stuffed animals so their parents can't hear.

TL;博士（这TL;博士是 @ sp00m下面接听）

tl;dr (this tl;dr is from @sp00m answer below)

$ EMIT调度一个事件向上... $广播向下调度一个事件

$emit dispatches an event upwards ... $broadcast dispatches an event downwards

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