Typescript
Table of Contents
1. basic
function greeter(person: string) { return "Hello, " + person } let user = "Yee" console.log(greeter(user))
Hello, Yee
function greeter(person: string) { return "Hello, " + person } "use strict"; let user = [2, 39] console.log(greeter(user))
../../../../tmp/babel-cIibwh/ts-src-IRbM7W.ts(6,21): error TS2345: Argument of type 'number[]' is not assignable to parameter of type 'string'. Hello, 2,39
class User{ Fristname:string Lastname:string Fullname:string constructor(firstname:string, lastname:string){ this.Fristname = firstname this.Lastname = lastname this.Fullname = this.Fristname+this.Lastname } } interface Person{ Fristname:string Lastname:string } function Greeter(Person){ return "hello, "+Person.Fristname + Person.Lastname } var user = new User("li", "san") console.log(Greeter(user))
../../../../tmp/babel-cIibwh/ts-src-DPsbOA.ts(17,18): error TS7006: Parameter 'Person' implicitly has an 'any' type. hello, lisan
2. callback
const n: number = 10 let qual = n => n*n; let m = (() => { console.log('nidh', n, qual(4)) return 9 })() console.log(m)
../../../../tmp/babel-KUfP9t/ts-src-HiNQhf.ts(2,12): error TS7006: Parameter 'n' implicitly has an 'any' type. nidh 10 16 9
let jj = ( (msg , didi) => { console.log(msg); didi(msg); return 9 } ) ( "kdiikkjkjk", msg => { console.log(msg); } ) console.log(jj)
../../../../tmp/babel-KUfP9t/ts-src-SG7pDT.ts(11,3): error TS7006: Parameter 'msg' implicitly has an 'any' type. kdiikkjkjk kdiikkjkjk 9
3. Generic
3.1. withour generic
function createArray(value: any, count: number): any[] { const arr: any[] = [] for (let index = 0; index < count; index++) { arr.push(value) } return arr } const arr1 = createArray(11, 3) const arr2 = createArray('aa', 3) console.log(arr1) console.log(arr2) console.log(arr1[0].toFixed(), arr2[0].split(''))
[ 11, 11, 11 ] [ 'aa', 'aa', 'aa' ] 11 [ 'a', 'a' ]
3.2. with generic
function createArray2 <T> (value: T, count: number):T[] { const arr: Array<T> = [] for (let index = 0; index < count; index++) { arr.push(value) } return arr } const arr3 = createArray2<number>(11, 3) console.log(arr3[0].toFixed()) // console.log(arr3[0].split('')) // error const arr4 = createArray2<string>('aa', 3) console.log(arr4[0].split('')) // console.log(arr4[0].toFixed()) // error
11 [ 'a', 'a' ]
3.3. advanced example
interface IbaseCRUD <T> { data: T[] add: (t: T) => void getById: (id: number) => T } class User { id?: number; //id主键自增 name: string; //姓名 age: number; //年龄 constructor (name, age) { this.name = name this.age = age } } class UserCRUD implements IbaseCRUD <User> { data: User[] = [] add(user: User): void { user = {...user, id: Date.now()} this.data.push(user) console.log('保存user', user.id) } getById(id: number): User { return this.data.find(item => item.id===id) } } const userCRUD = new UserCRUD() userCRUD.add(new User('tom', 12)) userCRUD.add(new User('tom2', 13)) console.log(userCRUD.data)
../../../../tmp/babel-VDC0rp/ts-src-ub8Ktp.ts(13,16): error TS7006: Parameter 'name' implicitly has an 'any' type.
../../../../tmp/babel-VDC0rp/ts-src-ub8Ktp.ts(13,22): error TS7006: Parameter 'age' implicitly has an 'any' type.
保存user 1629717666420
保存user 1629717666424
[
{ name: 'tom', age: 12, id: 1629717666420 },
{ name: 'tom2', age: 13, id: 1629717666424 }
]
3.4. interface
class User{ Fristname:string Lastname:string Fullname:string constructor(firstname:string, lastname:string){ this.Fristname = firstname this.Lastname = lastname this.Fullname = this.Fristname+this.Lastname } } interface Person{ Fristname:string Lastname:string } function Greeter(Person){ return "hello, "+Person.Fristname + Person.Lastname } var user = new User("li", "san") console.log(Greeter(user))
../../../../tmp/babel-VDC0rp/ts-src-kkk0v4.ts(17,18): error TS7006: Parameter 'Person' implicitly has an 'any' type. hello, lisan
4. collection
var nn = 10.00002 console.log(+nn.toFixed(2))
10