如何在typescript中声明Map类型？

let myMap: Map<KeyType, ValueType> = new Map<KeyType, ValueType>();

let myMap: Map<string, number> = new Map<string, number>();

let myMap: Map<string, number> = new Map<string, number>();

myMap.set("key1", 1);
myMap.set("key2", 2);

console.log(myMap.get("key1")); // 输出: 1
console.log(myMap.has("key2")); // 输出: true

myMap.delete("key1");

console.log(myMap.size); // 输出: 1

myMap.clear();

console.log(myMap.size); // 输出: 0