Move the js module to a js_sys crate (#512)

* Move the `js` module to a `js_sys` crate

* Update js-sys tests to pass again

* Update binding_to_unimplemented_apis_doesnt_break_everything

Remove its dependency on the `js` module

* Update metadata for js-sys

* Fix the `closures` example

crates/js-sys/tests/all/WeakSet.rs

@@ -0,0 +1,157 @@
+#![allow(non_snake_case)]
+
+use project;
+
+#[test]
+fn new() {
+    project()
+        .file(
+            "src/lib.rs",
+            r#"
+            #![feature(use_extern_macros)]
+
+            extern crate wasm_bindgen;
+            extern crate js_sys;
+            use wasm_bindgen::prelude::*;
+
+            #[wasm_bindgen]
+            pub fn new_weak_set() -> js_sys::WeakSet {
+                js_sys::WeakSet::new()
+            }
+        "#,
+        )
+        .file(
+            "test.js",
+            r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                assert.equal(typeof wasm.new_weak_set(), "object");
+            }
+        "#,
+        )
+        .test()
+}
+
+#[test]
+fn has() {
+    project()
+        .file(
+            "src/lib.rs",
+            r#"
+            #![feature(use_extern_macros)]
+
+            extern crate wasm_bindgen;
+            extern crate js_sys;
+            use wasm_bindgen::prelude::*;
+
+            #[wasm_bindgen]
+            pub fn has_value(this: &js_sys::WeakSet, value: js_sys::Object) -> bool {
+                this.has(value)
+            }
+        "#,
+        )
+        .file(
+            "test.js",
+            r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let set = new WeakSet();
+                let value = {some: "value"};
+                set.add(value);
+                assert.equal(wasm.has_value(set, value), true);
+
+                let nonex = {nonexistent: "value"};
+                assert.equal(wasm.has_value(set, nonex), false);
+            }
+        "#,
+        )
+        .test()
+}
+
+#[test]
+fn add() {
+    project()
+        .file(
+            "src/lib.rs",
+            r#"
+            #![feature(use_extern_macros)]
+
+            extern crate wasm_bindgen;
+            extern crate js_sys;
+            use wasm_bindgen::prelude::*;
+
+            #[wasm_bindgen]
+            pub fn add_value(this: &js_sys::WeakSet, value: js_sys::Object) -> js_sys::WeakSet {
+                this.add(value)
+            }
+        "#,
+        )
+        .file(
+            "test.js",
+            r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let set = new WeakSet();
+                let value = {some: "value"};
+                wasm.add_value(set, value);
+                assert.equal(set.has(value), true);
+
+                assert.throws(() => { wasm.add_value(set, 1) }, TypeError);
+                assert.throws(() => { wasm.add_value(set, true) }, TypeError);
+                assert.throws(() => { wasm.add_value(set, "fail") }, TypeError);
+                assert.throws(() => { wasm.add_value(set, null) }, TypeError);
+                assert.throws(() => { wasm.add_value(set, undefined) }, TypeError);
+            }
+        "#,
+        )
+        .test()
+}
+
+#[test]
+fn delete() {
+    project()
+        .file(
+            "src/lib.rs",
+            r#"
+            #![feature(use_extern_macros)]
+
+            extern crate wasm_bindgen;
+            extern crate js_sys;
+            use wasm_bindgen::prelude::*;
+
+            #[wasm_bindgen]
+            pub fn delete_value(this: &js_sys::WeakSet, value: js_sys::Object) -> bool {
+                this.delete(value)
+            }
+        "#,
+        )
+        .file(
+            "test.js",
+            r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let set = new WeakSet();
+                let value = {some: "value"};
+                set.add(value);
+                assert.equal(wasm.delete_value(set, value), true);
+                assert.equal(set.has(value), false);
+                assert.equal(wasm.delete_value(set, value), false);
+
+                assert.equal(wasm.delete_value(set, 1), false);
+                assert.equal(wasm.delete_value(set, true), false);
+                assert.equal(wasm.delete_value(set, "false"), false);
+                assert.equal(wasm.delete_value(set, null), false);
+                assert.equal(wasm.delete_value(set, undefined), false);
+            }
+        "#,
+        )
+        .test()
+}