代码部分 function test (obj, deep = 0, result = []) {     let arr = [];     for (let key in obj) {         arr.push(key);         if (typeof obj[key] == 'object') {             let temp  = deep + 1;             let newArr = test(obj[key], temp, result);         }      }     if (typeof result[deep] != 'undefined') {         result[deep] = result[deep].concat(arr);     } else {         result[deep] = arr;     }     return result; } 结果如图