app

commit bda3fa80b703901f6f29e2bcafabd4859d9a1fce
parent f2418cfb9fa221460780fd7dae9301bde494f756
Author: triesap <triesap@radroots.dev>
Date:   Mon, 19 Jan 2026 07:57:32 +0000

app-lib: add locale helper

- add locale resolution helper

- add wasm locale lookup fallback

- add unit tests for locale resolution

- re-export locale helpers from app lib

Diffstat:
M
crates/app-lib/src/lib.rs
 | 
2
++
A
crates/app-lib/src/locale.rs
 | 
62
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 64 insertions(+), 0 deletions(-)
diff --git a/crates/app-lib/src/lib.rs b/crates/app-lib/src/lib.rs
@@ -3,6 +3,7 @@
 pub mod browser;
 pub mod fetch;
 pub mod geo;
+pub mod locale;
 pub mod path;
 pub mod query;
 pub mod sleep;
@@ -12,6 +13,7 @@ pub mod symbols;
 pub use browser::{browser_platform, BrowserPlatformInfo};
 pub use fetch::{fetch_json, FetchJsonError, FetchJsonErrorKind, FetchJsonResult};
 pub use geo::{geop_init, geop_is_valid, AppGeolocationPoint};
+pub use locale::{get_locale, resolve_locale};
 pub use path::{normalize_path, sanitize_path, trim_slashes};
 pub use query::{encode_query_params, encode_route};
 pub use sleep::sleep;
diff --git a/crates/app-lib/src/locale.rs b/crates/app-lib/src/locale.rs
@@ -0,0 +1,62 @@
+#![forbid(unsafe_code)]
+
+const DEFAULT_LOCALE: &str = "en";
+
+pub fn resolve_locale(locales: &[&str], navigator_locale: Option<&str>) -> String {
+    let fallback = locales.first().copied().unwrap_or(DEFAULT_LOCALE);
+    let fallback_lower = fallback.to_ascii_lowercase();
+    let Some(nav_locale) = navigator_locale else {
+        return fallback_lower;
+    };
+    let nav_lower = nav_locale.to_ascii_lowercase();
+    if locales
+        .iter()
+        .any(|locale| locale.eq_ignore_ascii_case(&nav_lower))
+    {
+        return nav_lower;
+    }
+    let prefix = nav_lower.chars().take(2).collect::<String>();
+    if !prefix.is_empty()
+        && locales
+            .iter()
+            .any(|locale| locale.eq_ignore_ascii_case(&prefix))
+    {
+        return prefix;
+    }
+    fallback_lower
+}
+
+pub fn get_locale(locales: &[&str]) -> String {
+    #[cfg(target_arch = "wasm32")]
+    {
+        let navigator_locale = web_sys::window().map(|window| window.navigator().language());
+        resolve_locale(locales, navigator_locale.as_deref())
+    }
+    #[cfg(not(target_arch = "wasm32"))]
+    {
+        resolve_locale(locales, None)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::resolve_locale;
+
+    #[test]
+    fn resolve_locale_prefers_exact_match() {
+        let locales = ["en", "fr"];
+        assert_eq!(resolve_locale(&locales, Some("fr")), "fr");
+    }
+
+    #[test]
+    fn resolve_locale_prefers_prefix_match() {
+        let locales = ["en", "fr"];
+        assert_eq!(resolve_locale(&locales, Some("fr-CA")), "fr");
+    }
+
+    #[test]
+    fn resolve_locale_falls_back() {
+        let locales = ["en", "fr"];
+        assert_eq!(resolve_locale(&locales, Some("es-ES")), "en");
+    }
+}