如何获取key-value数组中的key值

var obj = { key1: 'value1', key2: 'value2', key3: 'value3' };
for (var key in obj) {
  console.log(key); // 输出key1、key2、key3
}

var obj = { key1: 'value1', key2: 'value2', key3: 'value3' };
var keys = Object.keys(obj);
console.log(keys); // 输出["key1", "key2", "key3"]

var obj = { key1: 'value1', key2: 'value2', key3: 'value3' };
var entries = Object.entries(obj);
for (var [key, value] of entries) {
  console.log(key); // 输出key1、key2、key3
}