use tslib and --importHelpers

package.json

@@ -44,6 +44,7 @@
     "style-loader": "^0.23.1",
     "svg-inline-loader": "^0.8.0",
     "to-string-loader": "1.1.5",
+    "tslib": "^1.10.0",
     "typedoc": "^0.14.2",
     "typescript": "^3.5.2",
     "url-loader": "^2.0.0",

tsconfig.json

@@ -15,6 +15,7 @@
     "skipLibCheck": true,
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
+    "importHelpers": true,
     "lib": [
       "dom",
       "es5",

yarn.lock

@@ -6671,6 +6671,11 @@ truncate-utf8-bytes@^1.0.0:
   dependencies:
     utf8-byte-length "^1.0.1"
 
+tslib@^1.10.0:
+  version "1.10.0"
+  resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.10.0.tgz#c3c19f95973fb0a62973fb09d90d961ee43e5c8a"
+  integrity sha512-qOebF53frne81cf0S9B41ByenJ3/IuH8yJKngAX35CmiZySA0khhkovshKK+jGCaMnVomla7gVlIcc3EvKPbTQ==
+
 tslib@^1.8.1, tslib@^1.9.0:
   version "1.9.3"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.9.3.tgz#d7e4dd79245d85428c4d7e4822a79917954ca286"