使用Promise 实现每隔1s输出1，2，3……
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| var a = 0;
function timeCout(){
return new Promise((resolve)=>{
a++;
console.log(a);
setTimeout(()=>{
resolve();
},1000);
})
}
async function main(){
await timeCout();
main();
}
main();
|
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| const arr = [1, 2, 3]
arr.reduce((p, x) => {
return p.then(() => {
return new Promise(r => {
setTimeout(() => r(console.log(x)), 1000)
})
})
}, Promise.resolve())
|
