Guard open modules with api version >= 4

Author: fhammerschmidt

src/Playground.res

@@ -903,10 +903,13 @@ module Settings = {
     let onResetClick = evt => {
       ReactEvent.Mouse.preventDefault(evt)
 
-      let open_modules =
+      let open_modules = switch readyState.selected.apiVersion {
+      | V1 | V2 | V3 | UnknownVersion(_) => None
+      | V4 =>
         readyState.selected.libraries->Belt.Array.some(el => el === "@rescript/core")
           ? Some(["RescriptCore"])
           : None
+      }
 
       let defaultConfig = {
         Api.Config.module_system: "nodejs",

src/common/CompilerManagerHook.res

@@ -454,10 +454,13 @@ let useCompilerManager = (
           let instance = Compiler.make()
           let apiVersion = apiVersion->Version.fromString
 
-          let open_modules =
+          let open_modules = switch apiVersion {
+          | V1 | V2 | V3 | UnknownVersion(_) => None
+          | V4 =>
             libraries->Belt.Array.some(el => el === "@rescript/core")
               ? Some(["RescriptCore"])
               : None
+          }
 
           let config = {...instance->Compiler.getConfig, ?open_modules}
           instance->Compiler.setConfig(config)