add start_console_logging(bool) which accepts a flag.

Author: ratmice

CHANGELOG.md

@@ -61,8 +61,9 @@ You can find its changes [documented below](#070---2021-01-01).
 - `scroll_to_view` and `scroll_area_to_view` methods on `UpdateCtx`, `LifecycleCtx` and `EventCtx` ([#1976] by [@xarvic])
 - `Notification::route` ([#1978] by [@xarvic])
 - Build on OpenBSD ([#1993] by [@klemensn])
-- Scope: expose scoped state using state() and state_mut() ([#2082] by [@rjwittams]
-- Tabs: allow getting and setting the tab index of a Tabs widget ([#2082] by [@rjwittams]
+- Scope: expose scoped state using state() and state_mut() ([#2082] by [@rjwittams])
+- Tabs: allow getting and setting the tab index of a Tabs widget ([#2082] by [@rjwittams])
+- App: add start_console_logging(bool) which accepts a flag. ([#2102] by [@ratmice])
 
 ### Changed
 

druid/src/app.rs

@@ -185,9 +185,17 @@ impl<T: Data> AppLauncher<T> {
     ///
     /// # Panics
     ///
-    /// Panics if the subscriber fails to initialize, for example if a `tracing`/`tracing_wasm`
-    /// global logger was already set.
-    pub fn log_to_console(self) -> Self {
+    /// Panics if `enable` is `true` and the subscriber fails to initialize,
+    /// for example if a `tracing`/`tracing_wasm` global logger was already set.
+    ///
+    /// Never panics when `enable` is `false`, or have any other side effect.
+    ///
+    /// Passing in false is useful if you want to enable a global logger as feature
+    /// but log to console otherwise.
+    pub fn start_console_logging(self, enable: bool) -> Self {
+        if !enable {
+            return self;
+        }
         #[cfg(not(target_arch = "wasm32"))]
         {
             use tracing_subscriber::prelude::*;
@@ -214,6 +222,10 @@ impl<T: Data> AppLauncher<T> {
         self
     }
 
+    /// Calls `start_console_logging` with `true`.
+    pub fn log_to_console(self) -> Self {
+        self.start_console_logging(true)
+    }
     /// Use custom localization resource
     ///
     /// `resources` is a list of file names that contain strings. `base_dir`