function aa(){
return new Promise(function(resolve){
if (format === ‘csv‘) resolve(‘aa‘)
else reject(‘bb‘)
})
}
aa().then(res=>{
console.log(‘aaa---------res‘,res)
}).catch(err=>{
console.log(‘aaa---------err‘,err)
})原文：https://www.cnblogs.com/boonook/p/10839652.html