FUTURE: remove import assertions support for JavaScript (#23541)

Ref #17944, https://github.com/swc-project/swc/issues/8893

TypeScript removes the `assert` keywords in the transpile, so this PR
only works for JavaScript files

1 files changed, 10 insertions, 1 deletions

diff --git a/cli/main.rs b/cli/main.rs
index 142ae017c..3b103e780 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -29,6 +29,7 @@ mod worker;
 use crate::args::flags_from_vec;
 use crate::args::DenoSubcommand;
 use crate::args::Flags;
+use crate::args::DENO_FUTURE;
 use crate::util::display;
 use crate::util::v8::get_v8_flags_from_env;
 use crate::util::v8::init_v8_flags;
@@ -389,7 +390,15 @@ fn resolve_flags_and_init(
     // Using same default as VSCode:
     // https://github.com/microsoft/vscode/blob/48d4ba271686e8072fc6674137415bc80d936bc7/extensions/typescript-language-features/src/configuration/configuration.ts#L213-L214
     DenoSubcommand::Lsp => vec!["--max-old-space-size=3072".to_string()],
-    _ => vec![],
+    _ => {
+      if *DENO_FUTURE {
+        // deno_ast removes TypeScript `assert` keywords, so this flag only affects JavaScript
+        // TODO(petamoriken): Need to check TypeScript `assert` keywords in deno_ast
+        vec!["--no-harmony-import-assertions".to_string()]
+      } else {
+        vec![]
+      }
+    }
   };
 
   init_v8_flags(&default_v8_flags, &flags.v8_flags, get_v8_flags_from_env());