Promise.resolved
时间: 2023-04-11 20:01:20 浏览: 45
Promise.resolved 是一个 Promise 对象的静态方法,它返回一个已经被解决的 Promise 对象。这个方法可以用来快速创建一个已经被解决的 Promise 对象,而不需要手动调用 resolve 方法。
相关问题
promise.all promise.race
回答: Promise.all和Promise.race都是Promise的方法。Promise.all接收一个Promise数组作为参数,当所有的Promise都变为resolved状态时,返回一个包含所有Promise结果的数组;如果其中一个Promise变为rejected状态,返回的Promise会立即被reject,并且会传递第一个被reject的Promise的结果。\[1\]而Promise.race也接收一个Promise数组作为参数,但是它只要有一个Promise变为resolved或rejected状态,就会返回该Promise的结果,不再等待其他Promise的状态。\[2\]如果最先返回的Promise请求是reject状态,则Promise.race会抛出异常并终止执行。\[3\]
#### 引用[.reference_title]
- *1* *3* [Promise.all()、Promise.allSettled()、Promise.race()三兄弟的区别](https://blog.csdn.net/qq_38021296/article/details/115212461)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^control_2,239^v3^insert_chatgpt"}} ] [.reference_item]
- *2* [理解和使用Promise.all和Promise.race](https://blog.csdn.net/qq_36850813/article/details/80528663)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^control_2,239^v3^insert_chatgpt"}} ] [.reference_item]
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promise.allsetted
Promise.allSettled is a method in JavaScript that takes an iterable (like an array) of promises and returns a new promise. This new promise is fulfilled with an array of objects, each representing the outcome of each promise in the iterable. The objects in the array have two properties: "status" and "value".
The "status" property can have two values: "fulfilled" or "rejected", indicating whether the corresponding promise was resolved or rejected. The "value" property contains the resolved value of a fulfilled promise, or the reason for rejection in case of a rejected promise.
Here's an example usage of Promise.allSettled:
```javascript
const promises = [
Promise.resolve('Promise 1 resolved'),
Promise.reject('Promise 2 rejected'),
Promise.resolve('Promise 3 resolved')
];
Promise.allSettled(promises)
.then(results => {
console.log(results);
});
```
In this example, the `promises` array contains three promises. The first and third promises are resolved, while the second promise is rejected. Calling `Promise.allSettled(promises)` will return a new promise that resolves with an array of objects representing the outcome of each promise.
The `console.log(results)` statement will output the following array:
```javascript
[
{ status: 'fulfilled', value: 'Promise 1 resolved' },
{ status: 'rejected', reason: 'Promise 2 rejected' },
{ status: 'fulfilled', value: 'Promise 3 resolved' }
]
```
I hope this helps! Let me know if you have any more questions.