setting up flow parser

src/bin/dune

@@ -1,4 +1,4 @@
 (executable
  (public_name js_bundler)
  (name main)
- (libraries js_bundler))
+ (libraries js_bundler flow_parser))

src/bin/main.re

@@ -0,0 +1,20 @@
+
+
+let parse_source = source => {
+  let parse_options =
+    Some(
+      Flow_parser.Parser_env.{
+        esproposal_nullish_coalescing: false,
+        esproposal_optional_chaining: false,
+        esproposal_class_instance_fields: true,
+        esproposal_class_static_fields: true,
+        esproposal_decorators: true,
+        esproposal_export_star_as: true,
+        types: true,
+        types_in_comments: false,
+        use_strict: false,
+      },
+    );
+
+  Flow_parser.Parser_flow.program(source, ~parse_options);
+};