chore(travis): add preview builds

.travis.yml

@@ -11,13 +11,19 @@ env:
     - DISPLAY=:99.0
     - CHROME_BIN=chromium-browser
   matrix:
-    - SCRIPT="lint"
+    - SCRIPT=lint
     - SCRIPT="run-e2e-tests --fast"
+    - SCRIPT="run-e2e-tests --fast" PREVIEW=true
+matrix:
+  fast_finish: true
+  allow_failures:
+    - env: "SCRIPT=\"run-e2e-tests --fast\" PREVIEW=true"    
 before_install:
   - npm install -g gulp --no-optional
 before_script:
   - sh -e /etc/init.d/xvfb start
 install:
   - ./script/install.sh
+  - if [[ $PREVIEW == true ]]; then npm install --prefix public/docs/_examples angular/{core,common,compiler,platform-browser,platform-browser-dynamic,http,forms,router-deprecated,router,upgrade}-builds; fi
 script:
   - gulp $SCRIPT

script/install.sh

@@ -3,7 +3,7 @@
 set -ex -o pipefail
 
 npm install --no-optional
-(cd public/docs/_examples && npm install)
-(cd public/docs/_examples/_protractor && npm install)
+(cd public/docs/_examples && npm install --no-optional)
+(cd public/docs/_examples/_protractor && npm install --no-optional)
 npm run webdriver:update --prefix public/docs/_examples/_protractor
 gulp add-example-boilerplate