feat: add is_dumb public function

Author: ugur-eren

src/lib.rs

@@ -89,7 +89,7 @@ extern crate alloc;
 pub use crate::kb::Key;
 #[cfg(feature = "std")]
 pub use crate::term::{
-    user_attended, user_attended_stderr, Term, TermFamily, TermFeatures, TermTarget,
+    is_dumb, user_attended, user_attended_stderr, Term, TermFamily, TermFeatures, TermTarget,
 };
 #[cfg(feature = "std")]
 pub use crate::utils::{

src/term.rs

@@ -1,5 +1,6 @@
 use alloc::sync::Arc;
 use core::fmt::{Debug, Display};
+use std::env;
 use std::io::{self, Read, Write};
 #[cfg(any(unix, all(target_os = "wasi", target_env = "p1")))]
 use std::os::fd::{AsRawFd, RawFd};
@@ -568,6 +569,26 @@ impl Term {
     }
 }
 
+/// A fast way to check if the application has a dumb terminal.
+///
+/// On Unix: `TERM` environment variable is not set or set to `dumb`.
+///
+/// On Windows: `TERM` environment variable is explicitly set to `dumb`.
+/// Native windows terminals typically do not set the `TERM` environment variable.
+#[inline]
+pub fn is_dumb() -> bool {
+    #[cfg(windows)]
+    let default = false;
+
+    #[cfg(not(windows))]
+    let default = true;
+
+    match env::var("TERM") {
+        Ok(term) => term == "dumb",
+        Err(_) => default,
+    }
+}
+
 /// A fast way to check if the application has a user attended for stdout.
 ///
 /// This means that stdout is connected to a terminal instead of a

src/unix_term.rs

@@ -9,6 +9,7 @@ use std::os::fd::{AsRawFd, RawFd};
 #[cfg(not(target_os = "macos"))]
 use std::sync::OnceLock;
 
+use crate::is_dumb;
 use crate::kb::Key;
 use crate::term::Term;
 
@@ -30,10 +31,7 @@ pub(crate) fn is_a_color_terminal(out: &Term) -> bool {
         return false;
     }
 
-    match env::var("TERM") {
-        Ok(term) => term != "dumb",
-        Err(_) => false,
-    }
+    !is_dumb()
 }
 
 pub(crate) fn is_a_true_color_terminal(out: &Term) -> bool {

src/windows_term/mod.rs

@@ -24,9 +24,9 @@ use windows_sys::Win32::System::Console::{
 };
 use windows_sys::Win32::UI::Input::KeyboardAndMouse::VIRTUAL_KEY;
 
-use crate::common_term;
 use crate::kb::Key;
 use crate::term::{Term, TermTarget};
+use crate::{common_term, is_dumb};
 
 #[cfg(feature = "windows-console-colors")]
 mod colors;
@@ -67,10 +67,7 @@ pub(crate) fn is_a_color_terminal(out: &Term) -> bool {
         return false;
     }
     if msys_tty_on(out) {
-        return match env::var("TERM") {
-            Ok(term) => term != "dumb",
-            Err(_) => true,
-        };
+        return !is_dumb();
     }
     enable_ansi_on(out)
 }