TypeScript 照猫画虎

定义变量类型

const num: number = 1

定义函数参数类型

const init: (p: str) => void

	= function(param) {

		alert(param)

	}

定义外部变量

declare var document

document.str = 'hello'

原始类型

var age: number = 2

var rating = 98.25

var isReady: boolean = true

var hasData = true

var firstName: string = 'John'

var lastName = 'Papa'

Arrays and Indexers

var names: string[] = ['John', 'Dan', 'Aaron', 'Fritz']

var firstPerson: string

firstPerson = names[0]

Null and Undefined

var num: number = null

var str: string = null

var isHappy: boolean = null

var customer: {} = null

var age: number;

var customer = undefined

var quantity: number

var company = undefined

---

对象类型

// object

var square = { h: 10, w: 20 }

var points: Object = { x: 10, y: 20 }

// function

var multiply = function (x: number) {

	return x * x

}

var multiplyMore: Function;

multiplyMore = function (x: number) {

	return x * *

}

Functions

image

var myFunc = function (h: number, w:number) {

	return h * w

}

var myFunc = (h: number, w: number) => h * w

// Void (Used as the return type for functions that return no value)

var greetMe : (msg: string) => void

greetMe = function (msg) {

	console.log(msg)

}

greetMe('Hello!')

Function Interface

interface SquareFunction {

	// 接收一个number类型参数，返回一个number类型的值

	(x: number): number

}

var squareItBasic: SquareFunction = num => num * num

interface Rectangle {

	h: number

	w?: number

}

squareIt: (react: Rectangle) => number