27.根据key获取Object里面的值

// 例子
const obj = {
  a: [{ c: 3 }, { d: 4 }],
  b: {
    c: 4,
  },
};

console.log(getObjectPath(obj, "a.0.c")); // 输出: 3
console.log(getObjectPath(obj, "a[1].d")); // 输出: 4
console.log(getObjectPath(obj, "b.c")); // 输出: 5
console.log(getObjectPath(obj, "b.c.d.b")); // 输出: 5

答案：

function getObjectPath(obj, path){
    const keys = path.replace(/\[(\w+)\]/, ".$1").split('.')
    return keys.reduce((acc, key)=>{
        if(typeof(acc) === 'object' && acc !== null){
            if(key in acc){
                return acc[key];
            } else {
                return undefined;
            }
        }
        return undefined
    }, obj)
}