[exec Map] Map.prototype.values and Map.prototype.keys implementation (#874)

* Initial commit

* Improving on Map iterator

* Improvements on the iterator

* Almost finish the next method of MapIterator

* Add different kinds to next

* fmt

* Add function description. Add test.

* Added symbol_iterator method. Refactor to use exactly the same function as "entries". Added test for it, unignored pending test.

* Remove TODOs

* [exec Map] keys and values prototype methods

boa/src/builtins/map/mod.rs

@@ -50,12 +50,14 @@ impl BuiltIn for Map {
                 entries_function,
                 Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
             )
+            .method(Self::keys, "keys", 0)
             .method(Self::set, "set", 2)
             .method(Self::delete, "delete", 1)
             .method(Self::get, "get", 1)
             .method(Self::clear, "clear", 0)
             .method(Self::has, "has", 1)
             .method(Self::for_each, "forEach", 1)
+            .method(Self::values, "values", 0)
             .callable(false)
             .build();
 
@@ -134,6 +136,20 @@ impl Map {
         MapIterator::create_map_iterator(ctx, this.clone(), MapIterationKind::KeyAndValue)
     }
 
+    /// `Map.prototype.keys()`
+    ///
+    /// Returns a new Iterator object that contains the keys for each element in the Map object in insertion order.
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///  - [MDN documentation][mdn]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-map.prototype.keys
+    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/keys
+    pub(crate) fn keys(this: &Value, _: &[Value], ctx: &mut Context) -> Result<Value> {
+        MapIterator::create_map_iterator(ctx, this.clone(), MapIterationKind::Key)
+    }
+
     /// Helper function to set the size property.
     fn set_size(this: &Value, size: usize) {
         let size = DataDescriptor::new(
@@ -321,6 +337,20 @@ impl Map {
         Ok(Value::Undefined)
     }
 
+    /// `Map.prototype.values()`
+    ///
+    /// Returns a new Iterator object that contains the values for each element in the Map object in insertion order.
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///  - [MDN documentation][mdn]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-map.prototype.values
+    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/values
+    pub(crate) fn values(this: &Value, _: &[Value], ctx: &mut Context) -> Result<Value> {
+        MapIterator::create_map_iterator(ctx, this.clone(), MapIterationKind::Value)
+    }
+
     /// Helper function to get a key-value pair from an array.
     fn get_key_value(value: &Value) -> Option<(Value, Value)> {
         if let Value::Object(object) = value {

boa/src/builtins/map/tests.rs

@@ -210,6 +210,33 @@ fn has() {
     assert_eq!(result, "false");
 }
 
+#[test]
+fn keys() {
+    let mut engine = Context::new();
+    let init = r#"
+        const map1 = new Map();
+        map1.set('0', 'foo');
+        map1.set(1, 'bar');
+        const keysIterator = map1.keys();
+        let item1 = keysIterator.next();
+        let item2 = keysIterator.next();
+        let item3 = keysIterator.next();
+        "#;
+    forward(&mut engine, init);
+    let result = forward(&mut engine, "item1.value");
+    assert_eq!(result, "\"0\"");
+    let result = forward(&mut engine, "item1.done");
+    assert_eq!(result, "false");
+    let result = forward(&mut engine, "item2.value");
+    assert_eq!(result, "1");
+    let result = forward(&mut engine, "item2.done");
+    assert_eq!(result, "false");
+    let result = forward(&mut engine, "item3.value");
+    assert_eq!(result, "undefined");
+    let result = forward(&mut engine, "item3.done");
+    assert_eq!(result, "true");
+}
+
 #[test]
 fn for_each() {
     let mut engine = Context::new();
@@ -231,6 +258,33 @@ fn for_each() {
     assert_eq!(forward(&mut engine, "sizeSum"), "9");
 }
 
+#[test]
+fn values() {
+    let mut engine = Context::new();
+    let init = r#"
+        const map1 = new Map();
+        map1.set('0', 'foo');
+        map1.set(1, 'bar');
+        const valuesIterator = map1.values();
+        let item1 = valuesIterator.next();
+        let item2 = valuesIterator.next();
+        let item3 = valuesIterator.next();
+        "#;
+    forward(&mut engine, init);
+    let result = forward(&mut engine, "item1.value");
+    assert_eq!(result, "\"foo\"");
+    let result = forward(&mut engine, "item1.done");
+    assert_eq!(result, "false");
+    let result = forward(&mut engine, "item2.value");
+    assert_eq!(result, "\"bar\"");
+    let result = forward(&mut engine, "item2.done");
+    assert_eq!(result, "false");
+    let result = forward(&mut engine, "item3.value");
+    assert_eq!(result, "undefined");
+    let result = forward(&mut engine, "item3.done");
+    assert_eq!(result, "true");
+}
+
 #[test]
 fn modify_key() {
     let mut engine = Context::new();