LibJS: Implement Array.prototype.{shift,pop}

Author: https://github.com/linusg
Commit: https://github.com/SerenityOS/serenity/commit/c209ea19850
Pull-request: https://github.com/SerenityOS/serenity/pull/1523

Libraries/LibJS/Runtime/Array.cpp

@@ -47,6 +47,20 @@ Array::~Array()
 {
 }
 
+Value Array::shift()
+{
+    if (m_elements.size() == 0)
+        return js_undefined();
+    return Value(m_elements.take_first());
+}
+
+Value Array::pop()
+{
+    if (m_elements.size() == 0)
+        return js_undefined();
+    return Value(m_elements.take_last());
+}
+
 void Array::push(Value value)
 {
     m_elements.append(value);
@@ -82,5 +96,4 @@ bool Array::put_own_property(Object& this_object, const FlyString& property_name
     }
     return Object::put_own_property(this_object, property_name, value);
 }
-
 }

Libraries/LibJS/Runtime/Array.h

@@ -39,6 +39,8 @@ public:
     const Vector<Value>& elements() const { return m_elements; }
     Vector<Value>& elements() { return m_elements; }
 
+    Value shift();
+    Value pop();
     void push(Value);
 
 private:

Libraries/LibJS/Runtime/ArrayPrototype.cpp

@@ -35,6 +35,18 @@ namespace JS {
 
 ArrayPrototype::ArrayPrototype()
 {
+    put_native_function("shift", [](Object* this_object, const Vector<Value>&) -> Value {
+        ASSERT(this_object);
+        ASSERT(this_object->is_array());
+        return static_cast<Array*>(this_object)->shift();
+    });
+
+    put_native_function("pop", [](Object* this_object, const Vector<Value>&) -> Value {
+        ASSERT(this_object);
+        ASSERT(this_object->is_array());
+        return static_cast<Array*>(this_object)->pop();
+    });
+
     put_native_function("push", [](Object* this_object, const Vector<Value>& arguments) -> Value {
         if (arguments.is_empty())
             return js_undefined();

Libraries/LibJS/Tests/Array.prototype.pop.js

@@ -0,0 +1,19 @@
+function assert(x) { if (!x) throw 1; }
+
+try {
+    var a = [1, 2, 3];
+    var value = a.pop();
+    assert(value === 3);
+    assert(a.length === 2);
+    assert(a[0] === 1);
+    assert(a[1] === 2);
+
+    var a = [];
+    var value = a.pop();
+    assert(value === undefined);
+    assert(a.length === 0);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}

Libraries/LibJS/Tests/Array.prototype.shift.js

@@ -0,0 +1,19 @@
+function assert(x) { if (!x) throw 1; }
+
+try {
+    var a = [1, 2, 3];
+    var value = a.shift();
+    assert(value === 1);
+    assert(a.length === 2);
+    assert(a[0] === 2);
+    assert(a[1] === 3);
+
+    var a = [];
+    var value = a.shift();
+    assert(value === undefined);
+    assert(a.length === 0);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}