Implement WasmBindgen executor and reorganize

futures/src/executor.rs

@@ -4,23 +4,29 @@ mod null;
 #[cfg(feature = "thread-pool")]
 mod thread_pool;
 
-#[cfg(feature = "thread-pool")]
-pub use thread_pool::ThreadPool;
-
 #[cfg(feature = "tokio")]
 mod tokio;
 
 #[cfg(feature = "async-std")]
 mod async_std;
 
+#[cfg(target_arch = "wasm32")]
+mod wasm_bindgen;
+
 pub use null::Null;
 
+#[cfg(feature = "thread-pool")]
+pub use thread_pool::ThreadPool;
+
 #[cfg(feature = "tokio")]
 pub use self::tokio::Tokio;
 
 #[cfg(feature = "async-std")]
 pub use self::async_std::AsyncStd;
 
+#[cfg(target_arch = "wasm32")]
+pub use wasm_bindgen::WasmBindgen;
+
 use futures::Future;
 
 pub trait Executor: Sized {

futures/src/executor/wasm_bindgen.rs

@@ -0,0 +1,17 @@
+use crate::Executor;
+
+#[derive(Debug)]
+pub struct WasmBindgen;
+
+impl Executor for WasmBindgen {
+    fn new() -> Result<Self, futures::io::Error> {
+        Ok(Self)
+    }
+
+    fn spawn(
+        &self,
+        future: impl futures::Future<Output = ()> + Send + 'static,
+    ) {
+        wasm_bindgen_futures::spawn_local(future);
+    }
+}