add support for NO_COLOR

5 files changed, 18 insertions, 3 deletions

diff --git a/README.md b/README.md
index f19b320..3ac15fd 100644
--- a/README.md
+++ b/README.md
@@ -378,7 +378,7 @@ long = true
 # How many lines of Rust are in this code base?
 # e.g. `erd --config rs`
 [rs]
-disk-usage = "word"
+disk-usage = "line"
 level = 1
 pattern = "\\.rs$"
 ```
diff --git a/example/.erdtree.toml b/example/.erdtree.toml
index a409e1b..1a84959 100644
--- a/example/.erdtree.toml
+++ b/example/.erdtree.toml
@@ -21,6 +21,6 @@ long = true
 
 # How many lines of Rust are in this code base?
 [rs]
-disk-usage = "word"
+disk-usage = "line"
 level = 1
 pattern = "\\.rs$"
diff --git a/src/context/color.rs b/src/context/color.rs
index e9447be..caf39c7 100644
--- a/src/context/color.rs
+++ b/src/context/color.rs
@@ -1,4 +1,14 @@
 use clap::ValueEnum;
+use once_cell::sync::OnceCell;
+use std::{env, ffi::OsString};
+
+pub static NO_COLOR: OnceCell<Option<OsString>> = OnceCell::new();
+
+/// Reads in the `NO_COLOR` environment variable to determine whether or not to display color in
+/// the output.
+pub fn no_color_env() {
+    let _ = NO_COLOR.set(env::var_os("NO_COLOR"));
+}
 
 /// Enum to determine how the output should be colorized.
 #[derive(Clone, Copy, Debug, ValueEnum, PartialEq, Eq, Default)]
diff --git a/src/context/mod.rs b/src/context/mod.rs
index 21472ac..9d331d7 100644
--- a/src/context/mod.rs
+++ b/src/context/mod.rs
@@ -326,7 +326,11 @@ impl Context {
     /// the Coloring, and whether or not stdout is connected to a tty.
     ///
     /// If Coloring is Force then this will always evaluate to `false`.
-    pub const fn no_color(&self) -> bool {
+    pub fn no_color(&self) -> bool {
+        if color::NO_COLOR.get().is_some_and(Option::is_some) {
+            return true;
+        }
+
         match self.color {
             Coloring::Auto if !self.stdout_is_tty => true,
             Coloring::None => true,
diff --git a/src/main.rs b/src/main.rs
index 1fb61e5..9727aad 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -79,6 +79,7 @@ fn run() -> Result<(), Box<dyn Error>> {
         return Ok(());
     }
 
+    context::color::no_color_env();
     styles::init(ctx.no_color());
 
     let indicator = (ctx.stdout_is_tty && !ctx.no_progress).then(progress::Indicator::measure);