Add typescript as explicit dev dependency

package.json

@@ -33,6 +33,7 @@
     "prettier": "^1.13.6",
     "sass-loader": "^7.0.1",
     "ts-jest": "^22.4.6",
+    "typescript": "^3.0.1",
     "vue-template-compiler": "^2.5.16"
   },
   "browserslist": [

yarn.lock

@@ -7439,6 +7439,10 @@ typedarray@^0.0.6:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
+typescript@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.0.1.tgz#43738f29585d3a87575520a4b93ab6026ef11fdb"
+
 uglify-es@^3.3.4:
   version "3.3.9"
   resolved "https://registry.yarnpkg.com/uglify-es/-/uglify-es-3.3.9.tgz#0c1c4f0700bed8dbc124cdb304d2592ca203e677"