Merge pull request #70 from rustwasm/use-web-sys

Use the web-sys crate for the "Hello" example

Author: sendilkumarn

crate/Cargo.toml

@@ -26,5 +26,15 @@ console_error_panic_hook = { version = "0.1.5", optional = true }
 # allocator, however.
 wee_alloc = { version = "0.4.2", optional = true }
 
+[dependencies.web-sys]
+version = "0.3"
+features = [
+  "Document",
+  "Element",
+  "HtmlElement",
+  "Node",
+  "Window",
+]
+
 [features]
 default-features = ["console_error_panic_hook", "wee_alloc"]

crate/src/lib.rs

@@ -1,7 +1,8 @@
 #[macro_use]
 extern crate cfg_if;
-
+extern crate web_sys;
 extern crate wasm_bindgen;
+
 use wasm_bindgen::prelude::*;
 
 cfg_if! {
@@ -10,6 +11,9 @@ cfg_if! {
     if #[cfg(feature = "console_error_panic_hook")] {
         extern crate console_error_panic_hook;
         use console_error_panic_hook::set_once as set_panic_hook;
+    } else {
+        #[inline]
+        fn set_panic_hook() {}
     }
 }
 
@@ -23,36 +27,20 @@ cfg_if! {
     }
 }
 
-// Definitions of the functionality available in JS, which wasm-bindgen will
-// generate shims for today (and eventually these should be near-0 cost!)
-//
-// These definitions need to be hand-written today but the current vision is
-// that we'll use WebIDL to generate this `extern` block into a crate which you
-// can link and import. There's a tracking issue for this at
-// https://github.com/rustwasm/wasm-bindgen/issues/42
-//
-// In the meantime these are written out by hand and correspond to the names and
-// signatures documented on MDN, for example
+// Called by our JS entry point to run the example.
 #[wasm_bindgen]
-extern "C" {
-    type HTMLDocument;
-    static document: HTMLDocument;
-    #[wasm_bindgen(method)]
-    fn createElement(this: &HTMLDocument, tagName: &str) -> Element;
-    #[wasm_bindgen(method, getter)]
-    fn body(this: &HTMLDocument) -> Element;
-
-    type Element;
-    #[wasm_bindgen(method, setter = innerHTML)]
-    fn set_inner_html(this: &Element, html: &str);
-    #[wasm_bindgen(method, js_name = appendChild)]
-    fn append_child(this: &Element, other: Element);
-}
+pub fn run() -> Result<(), JsValue> {
+    set_panic_hook();
 
-// Called by our JS entry point to run the example
-#[wasm_bindgen]
-pub fn run() {
-    let val = document.createElement("p");
-    val.set_inner_html("Hello from Rust, WebAssembly, and Webpack!");
-    document.body().append_child(val);
+    let window = web_sys::window().expect("should have a Window");
+    let document = window.document().expect("should have a Document");
+
+    let p: web_sys::Node = document.create_element("p")?.into();
+    p.set_text_content(Some("Hello from Rust, WebAssembly, and Webpack!"));
+
+    let body = document.body().expect("should have a body");
+    let body: &web_sys::Node = body.as_ref();
+    body.append_child(&p)?;
+
+    Ok(())
 }