Test Node 8 on Travis (facebook#2659)

* Test Node 8 on Travis

We still test Node 7 on AppVeyor

* Update e2e-installs.sh

* Update e2e-kitchensink.sh

* Update e2e-simple.sh

* Update e2e-installs.sh

* Update e2e-kitchensink.sh

* Update e2e-installs.sh

* Update e2e-simple.sh

* Update e2e-simple.sh

* Update e2e-kitchensink.sh

* Update e2e-installs.sh

Author: gaearon

Diff for: .travis.yml

@@ -2,7 +2,7 @@
 language: node_js
 node_js:
   - 6
-  - 7
+  - 8
 cache:
   directories:
   - node_modules

Diff for: tasks/e2e-installs.sh

@@ -95,7 +95,11 @@ fi
 
 if hash npm 2>/dev/null
 then
-  npm cache clean
+  # npm 5 is too buggy right now
+  if [ $(npm -v | head -c 1) -eq 5 ]; then
+    npm i -g npm@^4.x
+  fi;
+  npm cache clean || npm cache verify
 fi
 
 # Prevent lerna bootstrap, we only want top-level dependencies

Diff for: tasks/e2e-kitchensink.sh

@@ -87,7 +87,11 @@ fi
 
 if hash npm 2>/dev/null
 then
-  npm cache clean
+  # npm 5 is too buggy right now
+  if [ $(npm -v | head -c 1) -eq 5 ]; then
+    npm i -g npm@^4.x
+  fi;
+  npm cache clean || npm cache verify
 fi
 
 # Prevent lerna bootstrap, we only want top-level dependencies

Diff for: tasks/e2e-simple.sh

@@ -86,7 +86,11 @@ fi
 
 if hash npm 2>/dev/null
 then
-  npm cache clean
+  # npm 5 is too buggy right now
+  if [ $(npm -v | head -c 1) -eq 5 ]; then
+    npm i -g npm@^4.x
+  fi;
+  npm cache clean || npm cache verify
 fi
 
 # Prevent lerna bootstrap, we only want top-level dependencies