add binding for includes

src/js.rs

@@ -177,4 +177,11 @@ extern {
     /// http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toString
     #[wasm_bindgen(method, js_name = toString)]
     pub fn to_string(this: &Array) -> String;
+
+    /// The includes() method determines whether an array includes a certain element, returning true or false as appropriate.
+    ///
+    /// http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes
+    #[wasm_bindgen(method)]
+    pub fn includes(this: &Array, value: JsValue, from_index: i32) -> bool;
+
 }

tests/all/js_globals/Array.rs

@@ -386,3 +386,39 @@ fn to_string() {
         "#)
         .test()
 }
+
+
+#[test]
+fn includes() {
+    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 array_includes(this: &js::Array, value: JsValue, from_index: i32) -> bool {
+                this.includes(value, from_index)
+            }
+
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let characters = [8, 5, 4, 3, 1, 2]
+                let isTwoIncluded = wasm.array_includes(characters, 2, 0);
+                let isNineIncluded = wasm.array_includes(characters, 9, 0);
+
+                assert.ok(isTwoIncluded);
+                assert.ok(!isNineIncluded);
+
+                let isThreeIncluded = wasm.array_includes(characters, 3, 4);
+                assert.ok(!isThreeIncluded);
+            }
+        "#)
+        .test()
+}