LibJS: Implement ImportCall and HostImportModuleDynamically

This allows us to load modules from scripts.
This can be dangerous as it can load arbitrary files. Because of that it
fails and throws by default. Currently, only js and JavaScriptTestRunner
enable the default hook.

This also adds tests to test-js which test module code. Because we
form a spec perspective can't "enter" a module this is the easiest way
to run tests without having to modify test-js to have special cases for
modules.
To specify modules in test-js we use the extension '.mjs' this is to
ensure the files are not executed. We do still want to lint these files
so the prettier scripts have changed to look for '.mjs' files as well.

1 files changed, 3 insertions, 1 deletions

diff --git a/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp b/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp
index 6ed697ea8e..a4aa7f7e44 100644
--- a/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp
+++ b/Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp
@@ -182,8 +182,10 @@ int main(int argc, char** argv)
     if (g_main_hook)
         g_main_hook();
 
-    if (!g_vm)
+    if (!g_vm) {
         g_vm = JS::VM::create();
+        g_vm->enable_default_host_import_module_dynamically_hook();
+    }
 
     Test::JS::TestRunner test_runner(test_root, common_path, print_times, print_progress, print_json);
     test_runner.run(test_glob);