async await codelab (#1659)

* Add WIP async await codelab

* Limit lines to 80 chars

* Round 1 of revisions:
  - add futures codelab to sidenav
  - add futures codelab to /codelabs page
  - update 'url' global to dart.dev
  - move futures codelab to /codelabs/async-await (formerly incorrectly placed in /language)
  - sundry content corrections in futures codelab

* Add more updates per language comments/suggestions review feedback

* Further small updates addressing review comments.

* Configure site.alert templates and update futures codelab w/ templates

* Add "Practicing" section iframe; slight restructure for "Errors" section

* Added dartpad examples

* Remove extra title

* Remove section head and use of "future object"

* Remove typos

* Punctuate all bulleted list items.

* Allow check-code to fail for dart dev builds

* Correct mistaken exclusion of check-code from builds

* Allow failure for check-code.sh

* Allow failure for both check-code and analyze-and-test-examples

* Updates per ux and tw review

* More updates per review from @sfshaza2

* Updates per latest sfshaza2 comments

* Incorporate first part of changes from UX round 2

* Correct typos, turn on latest DartPad UI, and misc small fxies

* Update descriptions for examples

* Add updates from observing test user

* Minor update for example missing a border, extra sentence for DartPad

* Re-organize introduction per latest feedback:
- Remove heading for introduction
- Remove DartPad example
- Eliminate "key terms" section
- Distribute key terms definitions across relevant portions codelab

* Remove "!" characters from "Putting it all together" section

* Adding changes from latest review

* Refactored sync / async comparison section into 2 columns

* Updated instructions before each example

* Add changes before switching markup back to single-column view

* Completed markup re-write

* Finished updates from latest review comments

* End with new lines for .travis.yml and .firebaserc

* Remove dartpad includes file, update nav per review comments

* Update codelab title

* Incorporate suggestions from latest review

* Enforce 80 char line limit

* Small changes from latest review

* Updates from latest review

* Test omitting refresh-code-excerpts.sh - failing built

* Remove test fix for build

* Some changes based on recent review

* Incorporate latest review items

* Remove 'before running it'

* Exercise applies to "Working with futures"

* More updates - latest review

* Add survey at the end of the codelab

.gitignore

@@ -10,6 +10,7 @@
 .pub
 .*-cache/
 .vscode
+.spelling
 _asset_bundler_cache
 _bookhtml
 _cache/

_config.yml

@@ -92,6 +92,30 @@ assets:
 
 future: true # In support of https://github.com/dart-lang/site-www/issues/1111
 
+## Site-wide shorthands
+
+os-list: [Windows, macOS, Linux]
+
+alert:
+  important: >-
+    <aside class="alert alert-warning" role="alert" markdown="1">
+    <i class="fas fa-exclamation-circle"></i> **Important:**
+  info: >-
+    <aside class="alert alert-info" role="alert" markdown="1">
+    <i class="fas fa-info-circle"></i>
+  note: >-
+    <aside class="alert alert-info" role="alert" markdown="1">
+    <i class="fas fa-info-circle"></i> **Note:**
+  secondary: >-
+    <aside class="alert alert-secondary" role="alert" markdown="1">
+  tip: >-
+    <aside class="alert alert-success" role="alert" markdown="1">
+    <i class="far fa-lightbulb"></i> **Tip:**
+  warning: >-
+    <aside class="alert alert-warning" role="alert" markdown="1">
+    <i class="fas fa-exclamation-triangle"></i> **Warning:**
+  end: </aside>
+
 # bundler_args: --without production
 exclude: [diagrams]
 plugins: [jekyll-toc]

src/_data/side-nav.yml

@@ -6,12 +6,14 @@
     - title: Codelabs
       expanded: true
       children:
-        - title: Overview
+        - title: List of Dart codelabs
           urlExactMatch: true
           match-page-url-exactly: true
           permalink: /codelabs
-        - title: Cheatsheet codelab
+        - title: Language cheatsheet
           permalink: /codelabs/dart-cheatsheet
+        - title: "Asynchrony: futures, async, await"
+          permalink: /codelabs/async-await
     - title: Tutorials
       urlExactMatch: true
       match-page-url-exactly: true