Javascript 对象 - 检查并循环遍历对象中的数组

Question

I am trying to loop through an object literal and if a property is an array, I want to loop through that as well. The friends property of this object is an array, how would I test to see if it's iterable, then loop through it?

Thanks in advance,

  firstName: 'Jonas',
  lastName: 'Schmedtmann',
  age: 2037 - 1991,
  job: 'teacher',
  friends: ['Michael', 'Peter', 'Steven'],
};
const myObj = Object.entries(jonas);
for (const [key, val] of myObj) {
   //Some conditional statement here testing for an interable
   //Then loop through it to the console.
  console.log(key, val);
}

Answer 1

All arrays are instance of the Array class in Javascript so you can use var instanceof Array which returns a boolean to check if an element is an array or not, then iterate through it as you wish

 const obj = { firstName: 'Jonas', lastName: 'Schmedtmann', age: 2037 - 1991, job: 'teacher', friends: ['Michael', 'Peter', 'Steven'], }; const myObj = Object.entries(obj); for (const [key, val] of myObj) { //Some conditional statement here testing for an interable //Then loop through it to the console. if (val instanceof Array) { console.log('element is an array, printing now') print(val); } else console.log(key, val); } function print(ar) { ar.forEach(x => console.log(x)); }