Adds Array.prototype.splice() to js-sys (#571)

crates/js-sys/tests/wasm/Array.rs

@@ -96,6 +96,15 @@ fn slice() {
     assert_eq!(to_rust(&subset), array!["c", "x"]);
 }
 
+#[wasm_bindgen_test]
+fn splice() {
+    let characters = js_array!["a", "c", "x", "n", 1, "8"];
+    let removed = characters.splice(1, 3, &"b".into());
+
+    assert_eq!(to_rust(&removed), array!["c", "x", "n"]);
+    assert_eq!(to_rust(&characters), array!["a", "b", 1, "8"]);
+}
+
 #[wasm_bindgen_test]
 fn fill() {
     let characters = js_array!["a", "c", "x", "n", 1, "8"];