let bool:boolean = falselet num:number = 123let str:stringstr = "abc"str = `数值是${num}`let arr1: number[] = [1,2,3]let arr2: Array<number | string > = [1,2,3]let arr3: (string | number)[] = ['a',2,'c']let tuple: [string,number,boolean] = ['a',2,true]// 枚举enum Roles { SUPER_ADMIN = 0, ADMIN, USER}// any类型let value: anyvalue = "123"const arr4: any[]=[1,'b']// void类型let v: void = undefinedconst consoleText=(text: string): void =>{ console.log(text)}consoleText("abc")// null undefinedlet u: undefined = undefinedlet n: null = null// never类型const errorFunc = (message: string): never =>{ throw new Error(message)}const infiniterFunc =():never =>{ while(true){}}let neverVariable = (()=>{ while(true){}})// objectlet obj:object = { name : 'hequan',}// 类型断言const getLength = (target:string | number) : number =>{ if ((<string>target).length || (target as string).length === 0){ return (<string>target).length }else{ return target.toString().length }}Symbol

const s = Symbol("name") //唯一的值const info ={[s]:'hequan'}info[s]='123'Object.getOwnPropertySymbols(info)Reflect.ownKeys(info)const s1 = Symbol.for('he') // 全局注册 先查找是否存在，没有再创建Symbol.keyFor(s1) // 只查找 for创建的接口

"tslint.autoFixOnSave": true,tslint --init{ "root": false, "defaultSeverity": "error", "extends": [ "tslint:recommended" ], "jsRules": {}, "rules": { "quotemark": [false], "semicolon": [false], "interface-name": [true, "never-prefix"], "object-literal-sort-keys": [false] }, "rulesDirectory": []}interface NameInfo { firstName?: string, // ? 可选 lastName: string, // readonly lastName: string, [prop: string]: any}const getFullName = ({ firstName, lastName}: NameInfo): string => { return `${firstName}${lastName}`}getFullName({ firstName: "he", lastName: "quan", other: 1,} as NameInfo)interface RoleDic { [id: string]: string,}const role: RoleDic = { 0: 'super_admin', 1: 'admin',}interface User extends NameInfo { age: number,}const user1: User = { firstName: "t", lastName: "o", age: 11,}函数

let add: (x: number, y: number) => numberadd = (arg1: 1, arg2: 2): number => arg1 + arg2type Add = (x: number, y: number, z?: any) => number // 类型别名let addFunction = (x: number, y = 2) => x + ylet arr10 = [1, 2, 3]let arr11 = [...arr10]// 重载function handleData(x: string): string[]function handleData(x: number): number[]function handleData(x: any): any { if (typeof x === "string") { return x.split('') } else { return x.toString().split('').map((item) => Number(item)) }}泛型

const getArry = <T>(value: T, times: number = 5): T[] => { return new Array(times).fill(value)}getArry<number>(1234, 4).map((item) => item.toFixed())const getArray1 = <T, U>(param1: T, param2: U, times: number): Array<[T, U]> => { return new Array(times).fill([param1, param2])}getArray1<number, string>(1, 'a', 3).forEach((item) => { console.log(item[0]) console.log(item[1])})interface ValueWithLength { length: number}const getArray2 = <T extends ValueWithLength>(arg: T, times): T[] => { return new Array(times).fill(arg)}