// Copyright 2020 the V8 project authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

namespace array {

// https://tc39.es/proposal-item-method/#sec-array.prototype.at

transitioning javascript builtin ArrayPrototypeAt(

js-implicit context: NativeContext, receiver: JSAny)(index: JSAny): JSAny {

// 1. Let O be ? ToObject(this value).

const o = ToObject_Inline(context, receiver);

// 2. Let len be ? LengthOfArrayLike(O).

const len = GetLengthProperty(o);

// 3. Let relativeIndex be ? ToInteger(index).

const relativeIndex = ToInteger_Inline(index);

// 4. If relativeIndex ≥ 0, then

// a. Let k be relativeIndex.

// 5. Else,

// a. Let k be len + relativeIndex.

const k = relativeIndex >= 0 ? relativeIndex : len + relativeIndex;

// 6. If k < 0 or k ≥ len, then return undefined.

if (k < 0 || k >= len) {

return Undefined;

}

// 7. Return ? Get(O, ! ToString(k)).

return GetProperty(o, k);

}

}