Add get/set for TypedArrays. (#2001)

* Add get/set for `TypedArray`s.

* Change names.

* Change name to @pauan suggestion.

crates/js-sys/src/lib.rs

@@ -4884,6 +4884,14 @@ macro_rules! arrays {
             /// input values from a specified array.
             #[wasm_bindgen(method)]
             pub fn set(this: &$name, src: &JsValue, offset: u32);
+
+            /// Gets the value at `idx`, equivalent to the javascript `my_var = arr[idx]`.
+            #[wasm_bindgen(method, structural, indexing_getter)]
+            pub fn get_index(this: &$name, idx: u32) -> $ty;
+
+            /// Sets the value at `idx`, equivalent to the javascript `arr[idx] = value`.
+            #[wasm_bindgen(method, structural, indexing_setter)]
+            pub fn set_index(this: &$name, idx: u32, value: $ty);
         }
 
         impl $name {

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

@@ -89,6 +89,19 @@ fn new_fill() {
     each!(test_fill);
 }
 
+macro_rules! test_get_set {
+    ($arr:ident) => {{
+        let arr = $arr::new(&1.into());
+        assert_eq!(arr.get_index(0) as f64, 0 as f64);
+        arr.set_index(0, 1 as _);
+        assert_eq!(arr.get_index(0) as f64, 1 as f64);
+    }};
+}
+#[wasm_bindgen_test]
+fn new_get_set() {
+    each!(test_get_set);
+}
+
 macro_rules! test_slice {
     ($arr:ident) => {{
         let arr = $arr::new(&4.into());