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【js】Promise构造函数是同步执行还是异步执行，那么then方法呢？ #42

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misty0304 opened this issue Feb 27, 2020 · 1 comment

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misty0304 commented Feb 27, 2020

【js】Promise构造函数是同步执行还是异步执行，那么then方法呢？

Owner Author

misty0304 commented Feb 27, 2020 •

edited

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const promise = new Promise((resolve, reject) => {
console.log(1);
resolve(5);
console.log(2);
}).then(val => {
console.log(val);
});

promise.then(() => {
console.log(3);
});

console.log(4);

setTimeout(function() {
console.log(6);
});

执行结果: 124536
promise构造函数是同步执行的，then方法是异步执行的

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