const p1 = new Promise(function (resolve, reject) {
setTimeout(() => {console.timeEnd('start'); console.log(new Date());reject(new Error('fail'))}, 3000)
})

const p2 = new Promise(function (resolve, reject) {
console.time('start');
console.log(new Date());
setTimeout(() => {resolve(p1)}, 1000)
})

p2
.then(result => console.log(result))
.catch(error => console.log(error))
// Error: fail
这段代码执行时间为什么是3s多一点?
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