Updated typescript from 2 to 3.

package-lock.json

@@ -3885,9 +3885,9 @@
             "dev": true
         },
         "typescript": {
-            "version": "2.9.2",
-            "resolved": "http://registry.npm.taobao.org/typescript/download/typescript-2.9.2.tgz",
-            "integrity": "sha1-HL9h0F1rliaSROtqO85L2RTg8Aw=",
+            "version": "3.4.1",
+            "resolved": "https://mirrors.huaweicloud.com/repository/npm/typescript/-/typescript-3.4.1.tgz",
+            "integrity": "sha512-3NSMb2VzDQm8oBTLH6Nj55VVtUEpe/rgkIzMir0qVoLyjDZlnMBva0U6vDiV3IH+sl/Yu6oP5QwsAQtHPmDd2Q==",
             "dev": true
         },
         "uglify-js": {

package.json

@@ -28,7 +28,7 @@
         "gulp-typescript": "^5.0.1",
         "gulp-uglify": "^3.0.0",
         "live-server": "^1.2.0",
-        "typescript": "^2.6.2"
+        "typescript": "^3.4.1"
     },
     "dependencies": {}
 }