fix(module:dropdown): should always debouce before visible change

[Brooooooklyn]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ x ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

- [ ] Yes
- [ x ] No

Other information

resolve #234

[LinboLen]

how about just use css animation to implement it

…

在 2017年9月6日，下午3:20，LongYinan ***@***.***> 写道： PR Checklist Please check if your PR fulfills the following requirements: The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit <https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit> Tests for the changes have been added (for bug fixes / features) Docs have been added / updated (for bug fixes / features) PR Type What kind of change does this PR introduce? [ ] Bugfix [ ] Feature [ ] Code style update (formatting, local variables) [ ] Refactoring (no functional changes, no api changes) [ ] Build related changes [ ] CI related changes [ ] Documentation content changes [ ] Application (the showcase website) / infrastructure changes [ ] Other... Please describe: What is the current behavior? Issue Number: N/A What is the new behavior? Does this PR introduce a breaking change? [ ] Yes [ ] No Other information resolve #234 <#234> You can view, comment on, or merge this pull request online at: #237 <#237> Commit Summary fix(module:dropdown): should always debouce before subscribe visibleChange$ File Changes M src/components/dropdown/nz-dropdown-button.component.ts <https://github.com/NG-ZORRO/ng-zorro-antd/pull/237/files#diff-0> (1) M src/components/dropdown/nz-dropdown.component.ts <https://github.com/NG-ZORRO/ng-zorro-antd/pull/237/files#diff-1> (12) Patch Links: https://github.com/NG-ZORRO/ng-zorro-antd/pull/237.patch <https://github.com/NG-ZORRO/ng-zorro-antd/pull/237.patch> https://github.com/NG-ZORRO/ng-zorro-antd/pull/237.diff <https://github.com/NG-ZORRO/ng-zorro-antd/pull/237.diff> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#237>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AFNuQJHsAZXNyE-0lckFdWuziy5-6oLwks5sfkevgaJpZM4PN8YZ>.

[coveralls]

Coverage remained the same at 40.979% when pulling feb7d8d on Brooooooklyn:issue/dropdown-menus into 6b69cf9 on NG-ZORRO:master.