如何在AngularJS中使用$ scope。$ watch和$ scope。$ apply？

問題：

I don't understand how to use $scope.$watch and $scope.$apply . 我不明白如何使用$scope.$watch和$scope.$apply 。 The official documentation isn't helpful. 官方文檔沒有幫助。

What I don't understand specifically: 我不明白的是：

• Are they connected to the DOM? 他們鏈接到DOM嗎？
• How can I update DOM changes to the model? 如何更新對模型的DOM更改？
• What is the connection point between them? 它們之間的鏈接點是什麼？

I tried this tutorial , but it takes the understanding of $watch and $apply for granted. 我嘗試了本教程 ，但須要理解$watch和$apply是理所固然的。

What do $apply and $watch do, and how do I use them appropriately? $apply和$watch什麼做用，如何正確使用它們？

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解決方案：

參考一： https://stackoom.com/question/11PTM/如何在AngularJS中使用-scope-watch和-scope-apply
參考二： https://oldbug.net/q/11PTM/How-do-I-use-scope-watch-and-scope-apply-in-AngularJS