promise async await 结合 demo2

// 模拟 post 异步接口 begain
let post1 = ()=> {
    return new Promise((resolve, reject) => {
        setTimeout(()=>{
            reject('reject 2000')
        } , 2000)
    })
}
let post2 = ()=> {
    return new Promise((resolve, reject) => {
        setTimeout(()=>{
            resolve('success 1000')
        } , 1000)
    })
}
let post3 =  ()=> {
    return new Promise((resolve, reject) => {
        setTimeout(()=>{
            resolve('success 3000')
        } , 3000)
    })
}
let post4 =  ()=> {
    return new Promise((resolve, reject) => {
        setTimeout(()=>{
            reject('reject 4000')
        } , 4000)
    })
}
// 模拟 post 异步接口 end

　　2、

// 模拟 post 异步接口   try catch 方式 end
const getByApi5 = ()=> {
    return new Promise(async (resolve, reject)=>{
        try {
            const data = await post1()
            console.log('getP5 try 2s')
            resolve(data)
        }catch(e){
            console.log('getP5 catch 2s')
            reject(e)
        }
    })
}
const getByApi6 = ()=> {
    return new Promise(async (resolve, reject)=>{
        try {
            const data = await post2()
            console.log('getP6 try 1s')
            resolve(data)
        }catch(e){
            console.log('getP6 catch 1s')
            reject(e)
        }
    })
}
const getByApi7 = ()=> {
    return new Promise(async (resolve, reject)=>{
        try {
            const data = await post3()
            console.log('getP7 try 3s')
            resolve(data)
        }catch(e){
            console.log('getP7 catch 3s')
            reject(e)
        }
    })
}
const getByApi8 = ()=> {
    return new Promise(async (resolve, reject)=>{
        try {
            const data = await post4()
            console.log('getP8 try 4s')
            resolve(data)
        }catch(e){
            console.log('getP8 catch 4s')
            reject(e)
        }
    })
}

　　3、

Promise.all([getByApi5(), getByApi6(), getByApi7(), getByApi8()]).then((result) => {
    console.log('result')
    console.log(result)
}).catch((error) => {
    console.log('error')
    console.log(error)
})

　　4、区别在于， 2s 后， 走catch( error, 返回 reject 2000),  不会走 then

getP6 try 1s
getP5 catch 2s
error
reject 2000
getP7 try 3s
getP8 catch 4s