SOURCE

function at(object, arr) {
    let ans = [];
    for (let i = 0; i < arr.length; i++) {
        let temp = [];
        let ind = 0;
        temp[0] = object[arr[i][0]];
        for (let j = 1; j < arr[i].length; j++) {
            if (arr[i][j] != '.' && arr[i][j] != '[' && arr[i][j] != ']') {
                ind += 1;
                temp[ind] = temp[ind - 1][arr[i][j]];
            }
        }
        ans.push(temp[ind]);
    }
    return ans;
}

const object = {
    'a': [{
            'b': {
                'c': 3,
            },
        },
        4,
    ],
};

// 输出 [3, 4]
console.log(at(object, ['a[0].b.c', 'a[1]']));