TypeScript中Map对象使用及Map与字典的区别详解

//初始化Map的键和值，它们可以是任何类型,注意Map中所有的键或所有的值必须是相同类型
let nameList = new Map([
    ["key1", 1],
    ["key2", 2]
])
 
 //通过map.set设置键值对，返回该Map对象
nameList.set("key3", 3)
console.log(nameList)

//通过map.get获取键对应的值，如果不存在，则返回undefined
var getmap = nameList.get("key2")
var getmap2 = nameList.get("key999")
console.log(getmap)
console.log(getmap2)

//通过map.delete()删除键值对,删除则返回true，未删除则返回false
var deletemap = nameList.delete("key2")
console.log(deletemap)
console.log(nameList)

//通过has()判断 Map中是否包含所查找的键值，返回布尔型
var hasmap = nameList.has("key1")
var hasmap2 = nameList.has("key999")
console.log(hasmap)
console.log(hasmap2)

//通过clear()移除所有键值对，清楚Map
var clearmap = nameList.clear()
console.log(nameList)
 

let myMap = new Map()
myMap.set(0, "zero")
myMap.set(1, "one")

for (let [key, value] of myMap) {
  console.log(key, value)
}

let myMap = new Map()
myMap.set(0, "zero")
myMap.set(1, "one")

myMap.forEach((value, key) => {
  console.log(key, value)
})

let myMap = new Map()
myMap.set(0, "zero")
myMap.set(1, "one")

for (let key of myMap.keys()) {
  console.log(key)
}

let myMap = new Map()
myMap.set(0, "zero")
myMap.set(1, "one")

for (let value of myMap.values()) {
  console.log(value)
}

const map = new Map<string, number>();
map.set('apple', 1);
map.set('banana', 2);
map.set('orange', 3);

const dict = { 
  apple: 1,
  banana: 2,
  orange: 3,
};