【一起来烧脑】一步学会TypeScript入门

2019-07-18 本文已影响63人魔王哪吒

标题图

字符串新特性
变量和参数新特性
函数新特性
匿名函数
for of循环
TypeScript语言中的面向对象特性

理解ES5,ES6,JAVASCRIPT,TYPESCRIPT概念之间的关系

ES是客户端脚本语言的规范
ES5,ES6是这个规范的不同版本

JavaScript和TypeScript是两种不同的脚本语言
JavaScript实现了ES5规范
TypeScript实现了ES6规范

本地compiler

npm --version

sudo npm install -g typescript

tsc --version

ls

tsc Hello.ts

export class Hello {
}

"use strict";
var Hello = (function () {
 function Hello() {
 }
 return Hello;
}());
exports.Hello = Hello;

字符串新特性

function test(template, name, age) {
 console.log(template);
 console.log(name);
 console.log(age);
}
var myname = "da";

var getAge = function () {
 return 12;
}
test `hello my name is ${myname}, ${getAge()}`

参数类型

var myname: string = "da shu";

var a: any = "da shu";

var b: number = 12;

var man: boolean = true;

function test(name: string) :string {
 return "";
}

class Person {
 name: string;
 age: number;
}

var zhangsan: Person = new Person();
zhangsan.name = "da"
zhangsan.age = 223

参数默认值

参数类型：
在参数名称后面使用冒号来指定参数的类型
默认参数：
在参数声明后面用等号来指定参数的默认值

var myname: string = "da shu"

function test(a: string, b: string, c: string = "da"){
 console.log(a);
 console.log(b);
 console.log(c);
}

text("xx","yy","zz");

可选参数

var myname: string = "da shu"

function test(a: string, b?: string, c: string = "da"){
 console.log(a);
 console.log(b);
 console.log(c);
}

text("xx","yy","zz");

Rest and Spread操作符

function func1(...args) {
 args.forEach(function (arg) {
  console.log(arg);
 })
}

function func1() {
 var args = [];
 for( var _i = 0; _i < arguments.length; _i++) {
  args[_i - 0] = arguments[_i];
 }
 args.forEach(function(arg) {
  console.log(arg);
 });
}
func1(2,3,4);
func1(2,3,4,5,2);

function func1(a, b, c) {
 console.log(a);
 console.log(b);
 console.log(c);
}
var args = [1,2];
func1.applay(void 0, args);
var args2 = [23,32,2,211];
func1.apply(void 0, args2);

generator函数

Rest and Spread 操作符：
用来声明任意数量的方法参数

generator函数：
控制函数的执行过程，手工暂停和恢复代码执行

Babel是一个JavaScript编译器。

析构表达式

destructuring析构表达式：
通过表达式将对象或数组拆解成任意数量的变量

function getStock() {
 return {
  code: 'IBM',
  price: 100
 }
}
var { code, price } = getStock();
console.log(code);
console.log(price);

var array1 = [1,2,3,4];
function doSomething([number1,number2,...others]) {
 console.log(number1);
 console.log(number2);
 console.log(others);
}
doSomething(array1);

箭头表达式

用来声明匿名函数，消除传统匿名函数的this指针问题

var myArray = [1,2,3,4,5];
console.log(myArray.filter(value=> value%2==0));

function getStock(name: string) {
 this.name = name;
 setInterval(function(){
  consolv.log("name is :" + this.name);
  }, 1000);
}
var stock = new getStock("IBM");

function getStock(name) {
 this.name = name;
 setInterval(function(){
  console.log("name is" + this.name);
 }, 1000);
}
var  stock = new getStock("IBM");

结果没值

function getStock2(name: string) {
 this.name = name;
 setInterval(() => {
  consolv.log("name is :" + this.name);
  }, 1000);
}
var stock = new getStock("IBM");

有值了

for of循环

forEach()，for in，for of

面向对象：
类，泛型，接口，模块，注解，类型定义文件

for (var n of myArray) {
 if(n > 2) break;
 console.log(n);
}

TypeScript-类

class Person {
 name;
 eat() {
  console.log();
 }
}

var p1 = new Person();
p1.name = "da";
p1.eat();

image.png

构造函数

image.png

TypeScript-泛型

参数化的类型，一般用来限制集合的内容

TypeScript-接口

image.png

interface IPerson {
 name: string;
 age: number;
}
class Person {
 constructor(public config: IPerson) {
 }
}
var p1 = new Person({
 name: 'da',
 age: 12
});

interface Animal{
eat();
}
class Sheep implements Animal {
 eat() {
  console.log("");
 }
}
class Tiger implements Animal{
 eat() {
  console.log();
}
}