通過Promise實(shí)現(xiàn)sleep函數(shù)变擒，區(qū)別于循環(huán)，不堵塞線程
function sleep(ms) {
return new Promise(resolve => setTimeout(resolve, ms));
}
async function test() {
console.log('start test.');
await sleep(3000);
console.log('end test.');
}
test();
console.log('continue execute肾筐！');
