style(*): add prettier automation

Author: jshcrowthe

package.json

@@ -22,7 +22,8 @@
     "build:package": "gulp build && cd dist/package && npm install --production && npm shrinkwrap && npm pack && shx mv *.tgz ../",
     "test": "gulp build && gulp build:tests && gulp test && gulp test:integration",
     "dev": "gulp dev",
-    "commitmsg": "validate-commit-msg"
+    "commitmsg": "validate-commit-msg",
+    "precommit": "lint-staged"
   },
   "main": "index.js",
   "devDependencies": {
@@ -69,8 +70,10 @@
     "karma-mocha": "^1.3.0",
     "karma-spec-reporter": "^0.0.30",
     "karma-typescript": "^3.0.4",
+    "lint-staged": "^4.0.0",
     "merge2": "^1.0.3",
     "mkdirp": "^0.5.1",
+    "prettier": "^1.5.1",
     "require-dir": "^0.3.1",
     "rimraf": "^2.6.1",
     "shx": "^0.2.2",
@@ -98,5 +101,11 @@
     "cz-customizable": {
       "config": "./.cz-config.js"
     }
+  },
+  "lint-staged": {
+    "**/*.ts": [
+      "prettier --write {src,tests}/**/*.ts",
+      "git add"
+    ]
   }
 }