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

5 files changed, 26 insertions, 0 deletions

diff --git a/tests/specs/future/import_assertions/__test__.jsonc b/tests/specs/future/import_assertions/__test__.jsonc
new file mode 100644
index 000000000..a1e759c75
--- /dev/null
+++ b/tests/specs/future/import_assertions/__test__.jsonc
@@ -0,0 +1,16 @@
+{
+  "steps": [
+    {
+      "args": "run main.js",
+      "output": "error.out",
+      "exitCode": 1,
+      "envs": {
+        "DENO_FUTURE": "1"
+      }
+    },
+    {
+      "args": "run main.js",
+      "output": "success.out"
+    }
+  ]
+}
diff --git a/tests/specs/future/import_assertions/error.out b/tests/specs/future/import_assertions/error.out
new file mode 100644
index 000000000..cef663f35
--- /dev/null
+++ b/tests/specs/future/import_assertions/error.out
@@ -0,0 +1,4 @@
+error: Uncaught SyntaxError: Unexpected identifier 'assert'
+import foo from "./main.json" assert { type: "json" };
+                              ^
+    at <anonymous> (file:///[WILDCARD]/main.js:[WILDCARD])
diff --git a/tests/specs/future/import_assertions/main.js b/tests/specs/future/import_assertions/main.js
new file mode 100644
index 000000000..9b4c4d036
--- /dev/null
+++ b/tests/specs/future/import_assertions/main.js
@@ -0,0 +1,2 @@
+import foo from "./main.json" assert { type: "json" };
+console.log(foo);
diff --git a/tests/specs/future/import_assertions/main.json b/tests/specs/future/import_assertions/main.json
new file mode 100644
index 000000000..abdd5202b
--- /dev/null
+++ b/tests/specs/future/import_assertions/main.json
@@ -0,0 +1,3 @@
+{
+  "foo": "foo"
+}
diff --git a/tests/specs/future/import_assertions/success.out b/tests/specs/future/import_assertions/success.out
new file mode 100644
index 000000000..70ec274d9
--- /dev/null
+++ b/tests/specs/future/import_assertions/success.out
@@ -0,0 +1 @@
+{ foo: "foo" }