异步函数

aysnc异步函数就是时代发展的趋势

利用es6的promise的方法实现

function shaoshui(){
            return new Promise((resolve,reject)=>{
                setTimeout(()=>{
                    console.log('水开啦');
                    resolve('开水');
                },2000)
            })
        }
        // shaoshui().then(water=>{
        //     console.log('第一壶',water)
        //     return shaoshui()
        // }).then(water=>{
        //     console.log('第二壶',water)
        // })
        // 异步函数
        async function shaosanhushui(){
            const water1 =await shaoshui()
            console.log(water1)
            const water2 =await shaoshui()
            console.log(water2)
            const water3 =await shaoshui()
            console.log(water3)
            const water4 =await shaoshui()
            console.log(water4)
        }
        shaosanhushui()