Add web front-end and fix API issues

node_modules/rxjs/src/tsconfig.cjs.spec.json

@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.cjs.json",
+  /**
+   * this is pseudo config for test case's relative path resolution to `../src`, runs
+   * cjs config once more instead of manual copying to utilize incremental build.
+   */
+  "compilerOptions": {
+    "outDir": "../dist/src"
+  }
+}