feat(nodejs): Add expected_version variable

docs/config/README.md

@@ -2829,11 +2829,12 @@ By default the module will be shown if any of the following conditions are met:
 
 ### Variables
 
-| Variable | Example    | Description                          |
-| -------- | ---------- | ------------------------------------ |
-| version  | `v13.12.0` | The version of `node`                |
-| symbol   |            | Mirrors the value of option `symbol` |
-| style\*  |            | Mirrors the value of option `style`  |
+| Variable         | Example    | Description                                                              |
+| ---------------- | ---------- | ------------------------------------------------------------------------ |
+| version          | `v13.12.0` | The version of `node`                                                    |
+| expected_version | `>=12.0.0` | Optional `node` version as set in the engines property of `package.json` |
+| symbol           |            | Mirrors the value of option `symbol`                                     |
+| style\*          |            | Mirrors the value of option `style`                                      |
 
 *: This variable can only be used as a part of a style string
 

src/modules/nodejs.rs

@@ -71,6 +71,20 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
                 }
                 _ => None,
             })
+            .map(|variable| match variable {
+                "expected_version" => {
+                    let version = nodejs_version.as_deref();
+                    let expected_version = get_engines_version(context);
+                    let versions_in_range =
+                        check_engines_version(version, get_engines_version(context));
+
+                    match (expected_version, versions_in_range) {
+                        (Some(ver), false) => Some(Ok(ver)),
+                        _ => None,
+                    }
+                }
+                _ => None,
+            })
             .parse(None, Some(context))
     });
 
@@ -269,6 +283,80 @@ mod tests {
         assert_eq!(expected, actual);
         dir.close()
     }
+
+    #[test]
+    fn show_expected_version_when_engines_does_not_match() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let mut file = File::create(dir.path().join("package.json"))?;
+        file.write_all(
+            b"{
+            \"engines\":{
+                \"node\":\"<=11.0.0\"
+            }
+        }",
+        )?;
+        file.sync_all()?;
+
+        let actual = ModuleRenderer::new("nodejs")
+            .path(dir.path())
+            .config(toml::toml! {
+                [nodejs]
+                format = "via [$symbol($version )($expected_version )]($style)"
+            })
+            .collect();
+        let expected = Some(format!(
+            "via {}",
+            Color::Red.bold().paint(" v12.0.0 <=11.0.0 ")
+        ));
+
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn do_not_show_expected_version_if_engines_match() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let mut file = File::create(dir.path().join("package.json"))?;
+        file.write_all(
+            b"{
+            \"engines\":{
+                \"node\":\">=12.0.0\"
+            }
+        }",
+        )?;
+        file.sync_all()?;
+
+        let actual = ModuleRenderer::new("nodejs")
+            .path(dir.path())
+            .config(toml::toml! [
+                [nodejs]
+                format = "via [$symbol($version )($expected_version )]($style)"
+            ])
+            .collect();
+        let expected = Some(format!("via {}", Color::Green.bold().paint(" v12.0.0 ")));
+
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn do_not_show_expected_version_if_no_set_engines_version() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        File::create(dir.path().join("package.json"))?.sync_all()?;
+
+        let actual = ModuleRenderer::new("nodejs")
+            .path(dir.path())
+            .config(toml::toml! {
+                [nodejs]
+                format = "via [$symbol($version )($expected_version )]($style)"
+            })
+            .collect();
+        let expected = Some(format!("via {}", Color::Green.bold().paint(" v12.0.0 ")));
+
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
     #[test]
     fn no_node_installed() -> io::Result<()> {
         let dir = tempfile::tempdir()?;