TS Basics

notes ：TS In the syntax , No embellishments , You're going to report a mistake

This article just introduces TS Basic syntax , It will be updated later TS Deep content

1、 Boolean type

Modifier   :boolean    :Boolean

var time:boolean = true;// Qualifier shorthand 
time = new boolean(true);// This format is in TS An error is reported in Chinese grammar 
var time3:Boolean = false;// Qualifier capitalization 
time3 = new Boolean(true);// No error in words 

2、 value type

Modifier   :number    :Number

var time:number = 1;
var times:Number = 2;
times = new Number(3);

3、 String type

Modifier   :string    :String

var time:string = "abc";
var times:String = "abcdd";

4、 Undefined type

Modifier   :undefined

var b:undefined = undefined;  

5、 Or the use can be number It can also be undefined

var time:number|undefined;
time = 12;
time = undefined;

6、 function

function time(a: number, b? number, c: number = 1):number {
  return 12;
}
// There will be no error in the following two 

//  Don't use default values 
// time(1, 2, 3)
//  Use the default value 
time(1,2);

b?number Equate to number|undefined

c:number = 1; The default value is

function time():number  :number Is the type of return value

function time():void :void There is no return value

7、 An array type

7.1、 One dimensional array

var time:Array<number> = [1, 2, 3, 4]; //  It can only be of numerical type 

var time:Array<number|string> = [1 , 2, 3, "a"]; //  It can be a numeric type , It can also be a string type 

7.2、 Two dimensional array

var time:Array<Array<number|string>> = [
   [1, 2, "a" ],
   [1, 2, "a" ]
]

8、 A tuple type

//  Types must be in the same order as values 
var time:[number, string, boolean] = [1, "a", true];

9、 Enumeration type

Similar to the object , Its value is like a constant , Once defined, it cannot be changed , Equivalent to using the freezing method in the object

enum COLOR{RED, GREEN, PINK};
console.log(COLOR.RED,COLOR.PINK); // 0,2

enum COLOR{RED="red", GREEN="green", PINK="pink"};
console.log(COLOR.RED, COLOR.PINK); // red, pink

10、null type

var time:null = null;

11、any Any type

Don't know what type to give , Set to any type

However, it is not allowed to use any type No use ！！！

because TS It is originally a restricted type , You use the any It's all of any type , that TS It's useless .

var vb:any = 1;
vb = "a";