如何在JavaScript中向数组添加新元素并处理重复项及倒序返回最后3个元素？

function updateList(list, newElement) {
    // 初始化为空数组，处理非数组输入
    if (!Array.isArray(list)) {
        list = [];
    }

    // 对象深度比较函数
    const isEqual = (obj1, obj2) => {
        if (typeof obj1 !== 'object' || typeof obj2 !== 'object') {
            return obj1 === obj2;
        }
        const keys1 = Object.keys(obj1);
        const keys2 = Object.keys(obj2);
        if (keys1.length !== keys2.length) return false;
        return keys1.every(key => isEqual(obj1[key], obj2[key]));
    };

    // 查找并移除重复元素
    list = list.filter(item => !isEqual(item, newElement));

    // 添加新元素
    list.push(newElement);

    // 倒序返回末尾三个元素
    return list.slice(-3).reverse();
}

// 测试用例1
let list1 = [{ id: 2 }, { id: 3 }, { id: 4 }];
let newElement1 = { id: 2 };
console.log(updateList(list1, newElement1)); // 输出: [{id: 4}, {id: 3}, {id: 2}]


// 测试用例2
let list2 = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }];
let newElement2 = { id: 3 };
console.log(updateList(list2, newElement2)); // 输出: [{id: 3}, {id: 2}, {id: 1}]


// 测试用例3 (处理非数组输入)
let list3 = null;
let newElement3 = { id: 5 };
console.log(updateList(list3, newElement3)); // 输出: [{id: 5}]


// 测试用例4 (对象比较)
let list4 = [{name: 'apple', color: 'red'}, {name: 'banana', color: 'yellow'}];
let newElement4 = {name: 'apple', color: 'red'};
console.log(updateList(list4, newElement4)); // 输出: [{name: 'banana', color: 'yellow'}, {name: 'apple', color: 'red'}]