TU Tran

Currently, I have an existing application written in "Angular 1" and wish to implement new features in "Angular 2". Can you propose a plan for me?
There are 2 solution for situation, please consider as below:

Solution 1: Rebuild the whole application is suitable for small application or the budget is huge. this rarely applicable in real software development. As we usually migrate the current feature to "Angular 2" along with implement new features.
Solution 2: Build new features in "Angular 2" concurrently with migrating current feature from "Angular 1" to "Angular 2" one-by-one. This solution is more applicable in real work as the application can be used as normal. [More]

Ok, I have been read through part 1, But still not understand which case we should use attribute directive, could you tell me?
Attribute directive is a suitable solution when we want to modify current behavior or append new feature to HTML tag. [More]