feat(js) Implement Boolean bindings.

Cf https://github.com/rustwasm/wasm-bindgen/issues/275.

src/js.rs

@@ -243,6 +243,24 @@ extern {
     pub fn entries(this: &Array) -> ArrayIterator;
 }
 
+// Boolean
+#[wasm_bindgen]
+extern {
+    pub type Boolean;
+
+    /// The `Boolean()` constructor creates an object wrapper for a boolean value.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+    #[wasm_bindgen(constructor)]
+    pub fn new(value: JsValue) -> Boolean;
+
+    /// The `valueOf()` method returns the primitive value of a `Boolean` object.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean/valueOf
+    #[wasm_bindgen(method, js_name = valueOf)]
+    pub fn value_of(this: &Boolean) -> bool;
+}
+
 // Function
 #[wasm_bindgen]
 extern {

tests/all/js_globals/Boolean.rs

@@ -0,0 +1,55 @@
+#![allow(non_snake_case)]
+
+use project;
+
+#[test]
+fn new_undefined() {
+    project()
+        .file("src/lib.rs", r#"
+            #![feature(proc_macro, wasm_custom_section)]
+
+            extern crate wasm_bindgen;
+            use wasm_bindgen::prelude::*;
+            use wasm_bindgen::js;
+
+            #[wasm_bindgen]
+            pub fn new_boolean() -> js::Boolean {
+                js::Boolean::new(JsValue::undefined())
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                assert.equal(wasm.new_boolean().valueOf(), false);
+            }
+        "#)
+        .test()
+}
+
+#[test]
+fn new_truely() {
+    project()
+        .file("src/lib.rs", r#"
+            #![feature(proc_macro, wasm_custom_section)]
+
+            extern crate wasm_bindgen;
+            use wasm_bindgen::prelude::*;
+            use wasm_bindgen::js;
+
+            #[wasm_bindgen]
+            pub fn new_boolean() -> js::Boolean {
+                js::Boolean::new(JsValue::from("foo"))
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                assert.equal(wasm.new_boolean().valueOf(), true);
+            }
+        "#)
+        .test()
+}

tests/all/js_globals/mod.rs

@@ -4,6 +4,7 @@ use super::project;
 
 mod Array;
 mod ArrayIterator;
+mod Boolean;
 mod Date;
 mod Function;
 mod JsString;