Adding in to_vec method for typed arrays (#1844)

* Adding in to_vec method for typed arrays

* Fixing type error

crates/js-sys/src/lib.rs

@@ -4657,7 +4657,7 @@ pub fn global() -> Object {
 }
 
 macro_rules! arrays {
-    ($(#[doc = $ctor:literal] #[doc = $mdn:literal] $name:ident: $ty:ident,)*) => ($(
+    ($(#[doc = $ctor:literal] #[doc = $mdn:literal] $name:ident: $ty:ident => $zero:literal,)*) => ($(
         #[wasm_bindgen]
         extern "C" {
             #[wasm_bindgen(extends = Object)]
@@ -4792,6 +4792,14 @@ macro_rules! arrays {
                 )
             }
 
+            fn raw_copy_to(&self, dst: &mut [$ty]) {
+                let buf = wasm_bindgen::memory();
+                let mem = buf.unchecked_ref::<WebAssembly::Memory>();
+                let all_wasm_memory = $name::new(&mem.buffer());
+                let offset = dst.as_ptr() as usize / mem::size_of::<$ty>();
+                all_wasm_memory.set(self, offset as u32);
+            }
+
             /// Copy the contents of this JS typed array into the destination
             /// Rust slice.
             ///
@@ -4805,11 +4813,14 @@ macro_rules! arrays {
             /// different than the length of the provided `dst` array.
             pub fn copy_to(&self, dst: &mut [$ty]) {
                 assert_eq!(self.length() as usize, dst.len());
-                let buf = wasm_bindgen::memory();
-                let mem = buf.unchecked_ref::<WebAssembly::Memory>();
-                let all_wasm_memory = $name::new(&mem.buffer());
-                let offset = dst.as_ptr() as usize / mem::size_of::<$ty>();
-                all_wasm_memory.set(self, offset as u32);
+                self.raw_copy_to(dst);
+            }
+
+            /// Efficiently copies the contents of this JS typed array into a new Vec.
+            pub fn to_vec(&self) -> Vec<$ty> {
+                let mut output = vec![$zero; self.length() as usize];
+                self.raw_copy_to(&mut output);
+                output
             }
         }
 
@@ -4826,37 +4837,37 @@ macro_rules! arrays {
 arrays! {
     /// `Int8Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array
-    Int8Array: i8,
+    Int8Array: i8 => 0,
 
     /// `Int16Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array
-    Int16Array: i16,
+    Int16Array: i16 => 0,
 
     /// `Int32Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array
-    Int32Array: i32,
+    Int32Array: i32 => 0,
 
     /// `Uint8Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
-    Uint8Array: u8,
+    Uint8Array: u8 => 0,
 
     /// `Uint8ClampedArray()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray
-    Uint8ClampedArray: u8,
+    Uint8ClampedArray: u8 => 0,
 
     /// `Uint16Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array
-    Uint16Array: u16,
+    Uint16Array: u16 => 0,
 
     /// `Uint32Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array
-    Uint32Array: u32,
+    Uint32Array: u32 => 0,
 
     /// `Float32Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array
-    Float32Array: f32,
+    Float32Array: f32 => 0.0,
 
     /// `Float64Array()`
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array
-    Float64Array: f64,
+    Float64Array: f64 => 0.0,
 }

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

@@ -131,3 +131,10 @@ fn copy_to() {
         assert_eq!(*i, 5);
     }
 }
+
+#[wasm_bindgen_test]
+fn to_vec() {
+    let array = Int32Array::new(&10.into());
+    array.fill(5, 0, 10);
+    assert_eq!(array.to_vec(), vec![5, 5, 5, 5, 5, 5, 5, 5, 5, 5]);
+}