(Documentation): Utilities for Angular Display System

[AhyoungRyu]

What is this PR for?

This PR is related #591 created by @Leemoonsoo. I just added a section explaining the Utilities for Angular Display System to docs/angular.md.

What type of PR is it?

Documentation

Todos

• - Add a section for explaining Utilities for Angular Display System to angular.md

Is there a relevant Jira issue?

No. But there is a related PR: #591 (and maybe #588)

How should this be tested?

Just apply this PR and checkout the Display System -> Angular tab in Zeppelin web site.

Screenshots (if appropriate)

Questions:

• Does the licenses files need update? No.
• Is there breaking changes for older versions? No.
• Does this needs documentation? No.

[felixcheung]

After clicked button -> When the button is clicked
increased -> incremented

(where is numWatched defined?)

[AhyoungRyu]

numWatched value is defined in the image (<img src="/assets/themes/zeppelin/img/screenshots/display_angular2.png" width="60%" />).

[AhyoungRyu]

@felixcheung
Thank you for the comments. I applied them : )

[corneadoug]

as an view template of
-> as a view template for

[AhyoungRyu]

I should've checked more the existing documentation. Thank you for your review @corneadoug : )

[corneadoug]

@AhyoungRyu I think we should also specify that #591 is also for scala
@Leemoonsoo I'm just checking all the infos in that doc and would love your insight:

• AngularDisplay can be used only with scala?
• The new syntax introduced in Utilities for Angular Display system #591 is based on paragraphScope and notebookScope, however z.angularBind is based on notebookScope and globalScope. Shouldn't they all have the same scopes?

[Leemoonsoo]

AngularDisplay can be used only with scala?

Although AngularElem, AngularModel introduced in #591 is designed to be used in scala, ZeppelinDisplay module does not need to have that restriction. So it can provide API for the other language in the future.

The new syntax introduced in #591 is based on paragraphScope and notebookScope, however z.angularBind is based on notebookScope and globalScope. Shouldn't they all have the same scopes?

I'm planning to deprecate globalScope in the future while globalScope almost never get removed from notebook file and usage is quite limited.

Also z.angularBind() need to be deprecated while it's proving duplicated API after #591 merged, and i think #591 is better and easier API to use.

[doanduyhai]

Guys, I may update also this doc for my new PR about adding the same utilities function client-side: #678