Add date to utc string

src/js.rs

@@ -377,6 +377,13 @@ extern {
 extern {
     pub type Date;
     
+    /// The toUTCString() method converts a date to a string,
+    /// using the UTC time zone.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toUTCString
+    #[wasm_bindgen(method, js_name = toUTCString)]
+    pub fn to_utc_string(this: &Date) -> JsString;
+
     /// The valueOf() method  returns the primitive value of
     /// a Date object.
     ///

tests/all/js_globals/Date.rs

@@ -2,6 +2,33 @@
 
 use super::project;
 
+#[test]
+fn to_utc_string() {
+    project()
+        .file("src/lib.rs", r#"
+            #![feature(proc_macro, wasm_custom_section)]
+
+            extern crate wasm_bindgen;
+            use wasm_bindgen::prelude::*;
+            use wasm_bindgen::js::{Date, JsString};
+
+            #[wasm_bindgen]
+            pub fn to_utc_string(this: &Date) -> JsString {
+                this.to_utc_string()
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let date = new Date('14 Jun 2017 00:00:00 PDT');
+                assert.equal(wasm.to_utc_string(date), "Wed, 14 Jun 2017 07:00:00 GMT");
+            }
+        "#)
+        .test()
+}
+
 #[test]
 fn value_of() {
     project()