三个新秀语言分别在自己的领域统领江湖，但是语法确实非常像，还有一些关键词也挺像，集合在一起做个对比

    Typescript Dart Swift
    变量声明 let x:string = “ts”
    let x = “ts”
    var x = “ts” //不建议用    		 var x = “dart”
    String x = “dart”    		 var x = “dart”
    常量声明 const x:string = “ts” //只有类变量
    readonly x:string = “ts” //类和实例都可以用    		 const String x = “dart” //注意dart 中 const 意义相对更复杂 参考
    final String x = “dart”    		 let x = “dart”
    //swift中final类似Java，用于子类不可覆盖
    函数声明 helloWorld(name:string):string String helloWorld(String name) func helloWorld(name: String) -> String
    匿名函数 ()=>{} () {} 或者 ()=>返回变量 ()->type in code
    字符串format console.log(“hello “+”world “+name)
    console.log(hello world ${name})    		 print(“hello “ + “world “ +name)
    print(“hello world $name”)
    print(“hello world ${ 1 + 1}”)    		 print(“hello “ + “world “ +name)
    print(“hello wolrd \(name)”)
    方法引用 import {} from “”
    import “”
    import * as xx from “”    		 import “xxx.dart”
    import “”
    import “” as xxx;    		 import xxx;
    基本类型 字典
    let map = new Map();
    map.set(“lan”,”Typescript”);
    let lan = map.get(“lan”);//Typescript
    let map = {“lan”:”Typescript”};    		 字典
    var map = Map();
    map[“lan”] = “dart”;
    var lan = map[“lan”];
    var map = {“lan”:”dart”};    		 字典
    let map = String:String;
    map[“lan”] = “Swift”;
    let lan = map[“lan”];
    let map = [“lan”:”Swift”];