chore: add prettier

Author: jasoniangreen

package.json

@@ -7,6 +7,7 @@
     "test": "echo \"Error: no test specified\" && exit 1",
     "bundle": "gulp bundle",
     "dev": "gulp dev",
+    "prettier": "prettier --write",
     "gulp": "gulp"
   },
   "repository": {
@@ -31,6 +32,7 @@
     "gulp": "~3.9.0",
     "gulp-rename": "~1.2.2",
     "gulp-uglify": "~1.5.1",
+    "prettier": "1.14.3",
     "uglify-js": "~2.6.1",
     "vinyl-source-stream": "~1.1.0",
     "watchify": "~3.7.0"

prettier.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  trailingComma: "es5",
+  tabWidth: 4,
+  semi: true,
+  singleQuote: false
+};

yarn.lock

@@ -3186,6 +3186,11 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
   integrity sha1-gV7R9uvGWSb4ZbMQwHE7yzMVzks=
 
+[email protected]:
+  version "1.14.3"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.14.3.tgz#90238dd4c0684b7edce5f83b0fb7328e48bd0895"
+  integrity sha512-qZDVnCrnpsRJJq5nSsiHCE3BYMED2OtsI+cmzIzF1QIfqm5ALf8tEJcO27zV1gKNKRPdhjO0dNWnrzssDQ1tFg==
+
 pretty-hrtime@^1.0.0:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/pretty-hrtime/-/pretty-hrtime-1.0.3.tgz#b7e3ea42435a4c9b2759d99e0f201eb195802ee1"