Adding in more methods for Array (#1749)

Author: Pauan

crates/js-sys/src/lib.rs

@@ -130,10 +130,30 @@ extern "C" {
     #[derive(Clone, Debug, PartialEq, Eq)]
     pub type Array;
 
-    /// Creates a new empty array
+    /// Creates a new empty array.
     #[wasm_bindgen(constructor)]
     pub fn new() -> Array;
 
+    /// Creates a new array with the specified length (elements are initialized to `undefined`).
+    #[wasm_bindgen(constructor)]
+    pub fn new_with_length(len: u32) -> Array;
+
+    /// Retrieves the element at the index (returns `undefined` if the index is out of range).
+    #[wasm_bindgen(method, structural, indexing_getter)]
+    pub fn get(this: &Array, index: u32) -> JsValue;
+
+    /// Sets the element at the index (auto-enlarges the array if the index is out of range).
+    #[wasm_bindgen(method, structural, indexing_setter)]
+    pub fn set(this: &Array, index: u32, value: JsValue);
+
+    /// Deletes the element at the index (does nothing if the index is out of range).
+    ///
+    /// The element at the index is set to `undefined`.
+    ///
+    /// This does not resize the array, the array will still be the same length.
+    #[wasm_bindgen(method, structural, indexing_deleter)]
+    pub fn delete(this: &Array, index: u32);
+
     /// The `Array.from()` method creates a new, shallow-copied `Array` instance
     /// from an array-like or iterable object.
     #[wasm_bindgen(static_method_of = Array)]
@@ -405,6 +425,19 @@ extern "C" {
     pub fn unshift(this: &Array, value: &JsValue) -> u32;
 }
 
+// TODO pre-initialize the Array with the correct length using TrustedLen
+impl<A> std::iter::FromIterator<A> for Array where A: AsRef<JsValue> {
+    fn from_iter<T>(iter: T) -> Array where T: IntoIterator<Item = A> {
+        let out = Array::new();
+
+        for value in iter {
+            out.push(value.as_ref());
+        }
+
+        out
+    }
+}
+
 // ArrayBuffer
 #[wasm_bindgen]
 extern "C" {

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

@@ -1,4 +1,5 @@
 use js_sys::*;
+use std::iter::FromIterator;
 use wasm_bindgen::JsCast;
 use wasm_bindgen::JsValue;
 use wasm_bindgen_test::*;
@@ -25,6 +26,122 @@ fn to_rust(arr: &Array) -> Vec<JsValue> {
     result
 }
 
+#[wasm_bindgen_test]
+fn from_iter() {
+    assert_eq!(
+        to_rust(&vec![
+            JsValue::from("a"),
+            JsValue::from("b"),
+            JsValue::from("c"),
+        ].into_iter().collect()),
+        vec!["a", "b", "c"],
+    );
+
+    assert_eq!(
+        to_rust(&vec![
+            JsValue::from("a"),
+            JsValue::from("b"),
+            JsValue::from("c"),
+        ].iter().collect()),
+        vec!["a", "b", "c"],
+    );
+
+    let array = js_array![1u32, 2u32, 3u32];
+
+    assert_eq!(
+        to_rust(&vec![
+            array.clone(),
+        ].into_iter().collect()),
+        vec![JsValue::from(array.clone())],
+    );
+
+    assert_eq!(
+        to_rust(&vec![
+            array.clone(),
+        ].iter().collect()),
+        vec![JsValue::from(array)],
+    );
+
+    assert_eq!(
+        to_rust(&vec![
+            5,
+            10,
+            20,
+        ].into_iter().map(JsValue::from).collect()),
+        vec![5, 10, 20],
+    );
+
+    assert_eq!(
+        to_rust(&Array::from_iter(&[
+            JsValue::from("a"),
+            JsValue::from("b"),
+            JsValue::from("c"),
+        ])),
+        vec!["a", "b", "c"],
+    );
+
+    let v = vec![
+        "a",
+        "b",
+        "c",
+    ];
+
+    assert_eq!(
+        to_rust(&Array::from_iter(v.into_iter().map(|s| JsValue::from(s)))),
+        vec!["a", "b", "c"],
+    );
+}
+
+#[wasm_bindgen_test]
+fn new_with_length() {
+    let array = Array::new_with_length(5);
+    assert_eq!(array.length(), 5);
+    assert_eq!(array.get(4), JsValue::undefined());
+    array.set(4, JsValue::from("a"));
+    assert_eq!(array.get(4), "a");
+    assert_eq!(array.length(), 5);
+}
+
+#[wasm_bindgen_test]
+fn get() {
+    let array = js_array!["a", "c", "x", "n"];
+    assert_eq!(array.length(), 4);
+    assert_eq!(array.get(0), "a");
+    assert_eq!(array.get(3), "n");
+    assert_eq!(array.get(4), JsValue::undefined());
+}
+
+#[wasm_bindgen_test]
+fn set() {
+    let array = js_array!["a", "c", "x", "n"];
+    assert_eq!(array.length(), 4);
+    assert_eq!(array.get(0), "a");
+    array.set(0, JsValue::from("b"));
+    assert_eq!(array.get(0), "b");
+
+    assert_eq!(array.get(4), JsValue::undefined());
+    assert_eq!(array.length(), 4);
+    array.set(4, JsValue::from("d"));
+    assert_eq!(array.length(), 5);
+    assert_eq!(array.get(4), "d");
+
+    assert_eq!(array.get(10), JsValue::undefined());
+    assert_eq!(array.length(), 5);
+    array.set(10, JsValue::from("z"));
+    assert_eq!(array.length(), 11);
+    assert_eq!(array.get(10), "z");
+    assert_eq!(array.get(9), JsValue::undefined());
+}
+
+#[wasm_bindgen_test]
+fn delete() {
+    let array = js_array!["a", "c", "x", "n"];
+    assert_eq!(array.length(), 4);
+    assert_eq!(array.get(0), "a");
+    array.delete(0);
+    assert_eq!(array.get(0), JsValue::undefined());
+}
+
 #[wasm_bindgen_test]
 fn filter() {
     let array = js_array!["a", "c", "x", "n"];