feat: TC39 decorator proposal support (#22040)

This commit adds support for [TC39 Decorator
Proposal](https://github.com/tc39/proposal-decorators).

These decorators are only available in transpiled sources - ie.
non-JavaScript files (because of lack of support in V8).

This entails that "experimental TypeScript decorators" are not available
by default
and require to be configured, with a configuration like this:
```
{
  "compilerOptions": {
    "experimentalDecorators": true
  }
}
```


Closes https://github.com/denoland/deno/issues/19160

---------

Signed-off-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: crowlkats <crowlkats@toaxl.com>
Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>

2 files changed, 31 insertions, 15 deletions

diff --git a/cli/tests/integration/repl_tests.rs b/cli/tests/integration/repl_tests.rs
index 3c5c3e85f..0e63f1589 100644
--- a/cli/tests/integration/repl_tests.rs
+++ b/cli/tests/integration/repl_tests.rs
@@ -358,15 +358,26 @@ fn typescript_declarations() {
 
 #[test]
 fn typescript_decorators() {
-  util::with_pty(&["repl"], |mut console| {
-    console
-      .write_line("function dec(target) { target.prototype.test = () => 2; }");
-    console.expect("undefined");
-    console.write_line("@dec class Test {}");
-    console.expect("[class Test]");
-    console.write_line("new Test().test()");
-    console.expect("2");
-  });
+  let context = TestContextBuilder::default().use_temp_cwd().build();
+  let temp_dir = context.temp_dir();
+  temp_dir.write(
+    "./deno.json",
+    r#"{ "compilerOptions": { "experimentalDecorators": true } }"#,
+  );
+  let config_path = temp_dir.target_path().join("./deno.json");
+  util::with_pty(
+    &["repl", "--config", config_path.to_string_lossy().as_ref()],
+    |mut console| {
+      console.write_line(
+        "function dec(target) { target.prototype.test = () => 2; }",
+      );
+      console.expect("undefined");
+      console.write_line("@dec class Test {}");
+      console.expect("[class Test]");
+      console.write_line("new Test().test()");
+      console.expect("2");
+    },
+  );
 }
 
 #[test]
diff --git a/cli/tests/integration/run_tests.rs b/cli/tests/integration/run_tests.rs
index 3a2b46133..6c82cfeec 100644
--- a/cli/tests/integration/run_tests.rs
+++ b/cli/tests/integration/run_tests.rs
@@ -1508,8 +1508,13 @@ itest!(no_check {
 });
 
 itest!(no_check_decorators {
-  args: "run --quiet --reload --no-check run/no_check_decorators.ts",
-  output: "run/no_check_decorators.ts.out",
+  args: "run --quiet --reload --no-check run/decorators/experimental/no_check/main.ts",
+  output: "run/decorators/experimental/no_check/main.out",
+});
+
+itest!(decorators_tc39_proposal {
+  args: "run --quiet --reload --check run/decorators/tc39_proposal/main.ts",
+  output: "run/decorators/tc39_proposal/main.out",
 });
 
 itest!(check_remote {
@@ -1526,8 +1531,8 @@ itest!(no_check_remote {
 });
 
 itest!(runtime_decorators {
-  args: "run --quiet --reload --no-check run/runtime_decorators.ts",
-  output: "run/runtime_decorators.ts.out",
+  args: "run --quiet --reload --no-check run/decorators/experimental/runtime/main.ts",
+  output: "run/decorators/experimental/runtime/main.out",
 });
 
 itest!(seed_random {
@@ -1591,8 +1596,8 @@ itest!(ts_type_imports {
 });
 
 itest!(ts_decorators {
-  args: "run --reload --check run/ts_decorators.ts",
-  output: "run/ts_decorators.ts.out",
+  args: "run --reload --check run/decorators/experimental/ts/main.ts",
+  output: "run/decorators/experimental/ts/main.out",
 });
 
 itest!(ts_type_only_import {