LibJS: Add Array.prototype.every

Author: https://github.com/Lubrsi 🔰
Commit: https://github.com/SerenityOS/serenity/commit/57d15acd4cb
Pull-request: https://github.com/SerenityOS/serenity/pull/2322
Reviewed-by: https://github.com/linusg ✅

Libraries/LibJS/Runtime/ArrayPrototype.cpp

@@ -62,6 +62,7 @@ ArrayPrototype::ArrayPrototype()
     put_native_function("find", find, 1, attr);
     put_native_function("findIndex", find_index, 1, attr);
     put_native_function("some", some, 1, attr);
+    put_native_function("every", every, 1, attr);
     put("length", Value(0), Attribute::Configurable);
 }
 
@@ -560,4 +561,41 @@ Value ArrayPrototype::some(Interpreter& interpreter)
     return Value(false);
 }
 
+Value ArrayPrototype::every(Interpreter& interpreter)
+{
+    auto* array = array_from(interpreter);
+    if (!array)
+        return {};
+
+    auto* callback = callback_from_args(interpreter, "every");
+    if (!callback)
+        return {};
+
+    auto this_value = interpreter.argument(1);
+    auto array_size = array->elements().size();
+
+    for (size_t i = 0; i < array_size; ++i) {
+        if (i >= array->elements().size())
+            break;
+
+        auto value = array->elements().at(i);
+        if (value.is_empty())
+            continue;
+
+        MarkedValueList arguments(interpreter.heap());
+        arguments.append(value);
+        arguments.append(Value((i32)i));
+        arguments.append(array);
+
+        auto result = interpreter.call(*callback, this_value, move(arguments));
+        if (interpreter.exception())
+            return {};
+
+        if (!result.to_boolean())
+            return Value(false);
+    }
+
+    return Value(true);
+}
+
 }

Libraries/LibJS/Runtime/ArrayPrototype.h

@@ -57,6 +57,7 @@ private:
     static Value find(Interpreter&);
     static Value find_index(Interpreter&);
     static Value some(Interpreter&);
+    static Value every(Interpreter&);
 };
 
 }

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

@@ -0,0 +1,44 @@
+load("test-common.js");
+
+try {
+    assert(Array.prototype.every.length === 1);
+
+    assertThrowsError(() => {
+        [].every(undefined);
+    }, {
+        error: TypeError,
+        message: "undefined is not a function"
+    });
+
+    var arrayOne = ["serenity", { test: "serenity"} ];
+    var arrayTwo = [true, false, 1, 2, 3, "3"];
+
+    assert(arrayOne.every(value => value === "hello") === false);
+    assert(arrayOne.every(value => value === "serenity") === false);
+    assert(arrayOne.every((value, index, arr) => index < 2) === true);
+    assert(arrayOne.every(value => typeof(value) === "string") === false);
+    assert(arrayOne.every(value => arrayOne.pop()) === true);
+
+    assert(arrayTwo.every((value, index, arr) => index > 0) === false);
+    assert(arrayTwo.every((value, index, arr) => index >= 0) === true);
+    assert(arrayTwo.every(value => typeof(value) !== "string") === false);
+    assert(arrayTwo.every(value => typeof(value) === "number") === false);
+    assert(arrayTwo.every(value => value > 0) === false);
+    assert(arrayTwo.every(value => value >= 0 && value < 4) === true);
+    assert(arrayTwo.every(value => arrayTwo.pop()) === true);
+
+    assert(["", "hello", "friends", "serenity"].every(value => value.length >= 0) === true);
+    assert([].every(value => value === 1) === true);
+
+    arrayTwo = [true, false, 1, 2, 3, "3"];
+
+    // Every only goes up to the original length.
+    assert(arrayTwo.every((value, index, arr) => {
+        arr.push("serenity");
+        return value < 4;
+    }) === true);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}