Adding in Array::iter and Array::to_vec (#1909)

* Adding in Array::iter and Array::to_vec

* Changing ArrayIter to use std::ops::Range

crates/js-sys/src/lib.rs

@@ -425,6 +425,61 @@ extern "C" {
     pub fn unshift(this: &Array, value: &JsValue) -> u32;
 }
 
+/// Iterator returned by `Array::iter`
+#[derive(Debug, Clone)]
+pub struct ArrayIter<'a> {
+    range: std::ops::Range<u32>,
+    array: &'a Array,
+}
+
+impl<'a> std::iter::Iterator for ArrayIter<'a> {
+    type Item = JsValue;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let index = self.range.next()?;
+        Some(self.array.get(index))
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.range.size_hint()
+    }
+}
+
+impl<'a> std::iter::DoubleEndedIterator for ArrayIter<'a> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let index = self.range.next_back()?;
+        Some(self.array.get(index))
+    }
+}
+
+impl<'a> std::iter::FusedIterator for ArrayIter<'a> {}
+
+impl<'a> std::iter::ExactSizeIterator for ArrayIter<'a> {}
+
+impl Array {
+    /// Returns an iterator over the values of the JS array.
+    pub fn iter(&self) -> ArrayIter<'_> {
+        ArrayIter {
+            range: 0..self.length(),
+            array: self,
+        }
+    }
+
+    /// Converts the JS array into a new Vec.
+    pub fn to_vec(&self) -> Vec<JsValue> {
+        let len = self.length();
+
+        let mut output = Vec::with_capacity(len as usize);
+
+        for i in 0..len {
+            output.push(self.get(i));
+        }
+
+        output
+    }
+}
+
 // TODO pre-initialize the Array with the correct length using TrustedLen
 impl<A> std::iter::FromIterator<A> for Array
 where

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

@@ -81,6 +81,69 @@ fn from_iter() {
     );
 }
 
+#[wasm_bindgen_test]
+fn to_vec() {
+    let array = vec![JsValue::from("a"), JsValue::from("b"), JsValue::from("c")]
+        .into_iter()
+        .collect::<js_sys::Array>();
+
+    assert_eq!(array.to_vec(), vec![JsValue::from("a"), JsValue::from("b"), JsValue::from("c")]);
+}
+
+#[wasm_bindgen_test]
+fn iter() {
+    let array = vec![JsValue::from("a"), JsValue::from("b"), JsValue::from("c")]
+        .into_iter()
+        .collect::<js_sys::Array>();
+
+    assert_eq!(array.iter().collect::<Vec<JsValue>>(), vec![JsValue::from("a"), JsValue::from("b"), JsValue::from("c")]);
+
+    let mut iter = array.iter();
+
+    assert_eq!(iter.size_hint(), (3, Some(3)));
+    assert_eq!(iter.next(), Some(JsValue::from("a")));
+
+    assert_eq!(iter.size_hint(), (2, Some(2)));
+    assert_eq!(iter.next_back(), Some(JsValue::from("c")));
+
+    assert_eq!(iter.size_hint(), (1, Some(1)));
+    assert_eq!(iter.next_back(), Some(JsValue::from("b")));
+
+    assert_eq!(iter.size_hint(), (0, Some(0)));
+    assert_eq!(iter.next(), None);
+
+    assert_eq!(iter.size_hint(), (0, Some(0)));
+    assert_eq!(iter.next_back(), None);
+
+    let mut iter = array.iter();
+
+    assert_eq!(iter.size_hint(), (3, Some(3)));
+    assert_eq!(iter.next(), Some(JsValue::from("a")));
+
+    assert_eq!(iter.size_hint(), (2, Some(2)));
+    assert_eq!(iter.next(), Some(JsValue::from("b")));
+
+    assert_eq!(iter.size_hint(), (1, Some(1)));
+    assert_eq!(iter.next(), Some(JsValue::from("c")));
+
+    assert_eq!(iter.size_hint(), (0, Some(0)));
+    assert_eq!(iter.next(), None);
+
+    let mut iter = array.iter();
+
+    assert_eq!(iter.size_hint(), (3, Some(3)));
+    assert_eq!(iter.next_back(), Some(JsValue::from("c")));
+
+    assert_eq!(iter.size_hint(), (2, Some(2)));
+    assert_eq!(iter.next_back(), Some(JsValue::from("b")));
+
+    assert_eq!(iter.size_hint(), (1, Some(1)));
+    assert_eq!(iter.next_back(), Some(JsValue::from("a")));
+
+    assert_eq!(iter.size_hint(), (0, Some(0)));
+    assert_eq!(iter.next_back(), None);
+}
+
 #[wasm_bindgen_test]
 fn new_with_length() {
     let array = Array::new_with_length(5);