Merge pull request #187 from LinkunGao/release/v1.13.21

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Author: LinkunGao

tsconfig.json

@@ -11,7 +11,7 @@
     // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
 
     /* Language and Environment */
-    "target": "es5" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
+    "target": "es2015" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
     "lib": [
       "DOM",
       "ES2015"