js map 遍历 获取key

const myMap = new Map();
myMap.set('key1', 'value1');
myMap.set('key2', 'value2');
myMap.set('key3', 'value3');

// 获取键的迭代器
const keysIterator = myMap.keys();

// 遍历键
for (let key of keysIterator) {
  console.log(key); // 输出: key1, key2, key3
}

const myMap = new Map();
myMap.set('key1', 'value1');
myMap.set('key2', 'value2');
myMap.set('key3', 'value3');

// 记录要删除的键
const keysToRemove = [];

for (let key of myMap.keys()) {
  if (key === 'key2') {
    keysToRemove.push(key);
  }
}

// 遍历完成后删除键
keysToRemove.forEach(key => myMap.delete(key));

const myMap = new Map();

if (myMap.size > 0) {
  for (let key of myMap.keys()) {
    console.log(key);
  }
} else {
  console.log('Map is empty');
}

// 检查特定键是否存在
if (myMap.has('key1')) {
  console.log('key1 exists');
} else {
  console.log('key1 does not exist');
}