Examples of 13 basic types in typescript

1. Use literals for type declarations, and they cannot be modified after declarations

let a: 10;
// a = 10  可以  a = 11 不可以

2. You can use | to connect multiple types (joint types)

let c: boolean | string;
// c = true;  c = 'hha'; 可以  a = 123 不可以

3.any any type

一个变量设置类型为any后相当于对该变量关闭了TS类型检测
使用ts时，不建议使用any
let d; 声明变量不指定类型，TS解析器会自动判断变量的类型为any

4.unknown represents an unknown type of value

let e: unknown;
// unknown类型的值赋值给别的类型的会报错

5. Type assertion, you can tell the actual type of the parser variable

d = e as string;

Or write like this, tell the variable e is a string

d = <string>e;

6.viod is used to indicate empty, take function as an example, it means a function without return value

function fn(): void{
    
    
  // return 就报错
}

7.never means that the result will never be returned, it can be used like this

function fn1(): never{
    
    
  throw new Error('报错了')
}

8. Object, {} is used to specify which attributes can be included in the object

let obj2 : {
    
    name : string}
obj2 = {
    
    name : '孙悟空'}

Add after the attribute name? , Indicating that the attribute is optional

let obj2 : {
    
    name : string , age?:number};
obj2 = {
    
    name : '孙悟空',age:18}

[propName:string]:any represents any type of attribute,
as long as there is a name attribute in obj3, you can add other attributes at will

let obj3: {
    
    name:string,[propName:string]:any};
obj3 = {
    
    name:'哈哈',age:18,name2:'james'}

9. Arrow functions

const gg = (a:number,b:number) :number =>{
    
    
  return 1
}

10. Array

let arr1: string[]; //字符串数组
let arr2: number[]; //表示数值数组;

11. Tuples, which are fixed-length arrays

let yz: [string,string];
yz = ['hee','abc'];

12. Enumeration

enum Gender{
    
    
  Male = 0,
  Female = 1
}

let i: {
    
    name:string,gender:Gender};
i = {
    
    
  name:'孙悟空',
  gender:Gender.Male
}
console.log(i.gender === Gender.Male) //true

13.& means at the same time

let jj: {
    
    name:string} & {
    
    age:number};
jj = {
    
    name:'孙悟空',age:18}

Examples of 13 basic types in typescript

Guess you like