feat(cli): add "--no-clear-screen" flag (#13454)

This commit adds "--no-clear-screen" flag which can be used
with "--watch" flag to disable clearing of terminal screen on
each file change.

1 files changed, 48 insertions, 0 deletions

diff --git a/cli/tests/integration/watcher_tests.rs b/cli/tests/integration/watcher_tests.rs
index 89d4bf3f7..cdc7a2c98 100644
--- a/cli/tests/integration/watcher_tests.rs
+++ b/cli/tests/integration/watcher_tests.rs
@@ -997,3 +997,51 @@ fn test_watch_module_graph_error_referrer() {
   wait_for("Process failed", &mut stderr_lines);
   check_alive_then_kill(child);
 }
+
+#[test]
+fn watch_with_no_clear_screen_flag() {
+  let t = TempDir::new().unwrap();
+  let file_to_watch = t.path().join("file_to_watch.js");
+  write(&file_to_watch, "export const foo = 0;").unwrap();
+
+  // choose deno run subcommand to test --no-clear-screen flag
+  let mut child = util::deno_cmd()
+    .current_dir(util::testdata_path())
+    .arg("run")
+    .arg("--watch")
+    .arg("--no-clear-screen")
+    .arg("--unstable")
+    .arg(&file_to_watch)
+    .env("NO_COLOR", "1")
+    .stdout(std::process::Stdio::piped())
+    .stderr(std::process::Stdio::piped())
+    .spawn()
+    .unwrap();
+  let (_, mut stderr_lines) = child_lines(&mut child);
+
+  let next_line = stderr_lines.next().unwrap();
+
+  // no clear screen
+  assert!(!&next_line.contains(CLEAR_SCREEN));
+  assert_contains!(&next_line, "Process started");
+  assert_contains!(
+    stderr_lines.next().unwrap(),
+    "Process finished. Restarting on file change..."
+  );
+
+  // Change content of the file
+  write(&file_to_watch, "export const bar = 0;").unwrap();
+
+  let next_line = stderr_lines.next().unwrap();
+
+  // no clear screen
+  assert!(!&next_line.contains(CLEAR_SCREEN));
+
+  assert_contains!(&next_line, "Watcher File change detected! Restarting!");
+  assert_contains!(
+    stderr_lines.next().unwrap(),
+    "Process finished. Restarting on file change..."
+  );
+
+  check_alive_then_kill(child);
+}