如何实现promise.all ，promise.any，promise.any,promise.allSetlled

### 实现 `Promise.all` `Promise.all` 接收一个 Promise 数组，并在所有 Promise 成功完成后返回一个新的 Promise，其结果是一个数组，包含每个 Promise 的结果。如果有一个 Promise 被拒绝，则立即拒绝。 ```javascript function promiseAll(promises) { return new Promise((resolve, reject) => { if (!Array.isArray(promises)) { return reject(new TypeError('promises must be an array')); } const results = []; let resolvedCount = 0; for (let i = 0; i < promises.length; i++) { Promise.resolve(promises[i]) .then(value => { results[i] = value; resolvedCount++; if (resolvedCount === promises.length) { resolve(results); } }) .catch(error => { reject(error); }); } }); } ``` ### 实现 `Promise.any` `Promise.any` 接收一个 Promise 数组，并在任意一个 Promise 成功完成后立即返回该值。如果所有 Promise 都被拒绝，则返回一个聚合错误（AggregateError）。 ```javascript function promiseAny(promises) { return new Promise((resolve, reject) => { if (!Array.isArray(promises)) { return reject(new TypeError('promises must be an array')); } const errors = []; let rejectedCount = 0; for (let i = 0; i < promises.length; i++) { Promise.resolve(promises[i]) .then(value => { resolve(value); }) .catch(error => { errors[i] = error; rejectedCount++; if (rejectedCount === promises.length) { reject(new AggregateError(errors, 'All promises were rejected')); } }); } }); } ``` ### 实现 `Promise.allSettled` `Promise.allSettled` 接收一个 Promise 数组，并在所有 Promise 完成后（无论是成功还是失败）返回一个结果数组，每个元素表示对应 Promise 的状态和结果或原因。 ```javascript function promiseAllSettled(promises) { return new Promise((resolve, reject) => { if (!Array.isArray(promises)) { return reject(new TypeError('promises must be an array')); } const results = []; let settledCount = 0; for (let i = 0; i < promises.length; i++) { Promise.resolve(promises[i]) .then(value => { results[i] = { status: 'fulfilled', value }; settledCount++; if (settledCount === promises.length) { resolve(results); } }) .catch(reason => { results[i] = { status: 'rejected', reason }; settledCount++; if (settledCount === promises.length) { resolve(results); } }); } }); } ``` ### 使用示例 #### 示例：`promiseAll` ```javascript const p1 = Promise.resolve(3); const p2 = new Promise((resolve, reject) => { setTimeout(resolve, 100, 'foo'); }); const p3 = Promise.reject('出错了'); promiseAll([p1, p2, p3]) .then(values => console.log(values)) .catch(error => console.error(error)); ``` #### 示例：`promiseAny` ```javascript const p1 = Promise.reject('出错了1'); const p2 = new Promise((resolve, reject) => { setTimeout(reject, 100, '出错了2'); }); const p3 = Promise.resolve(3); promiseAny([p1, p2, p3]) .then(value => console.log(value)) .catch(error => console.error(error)); ``` #### 示例：`promiseAllSettled` ```javascript const p1 = Promise.resolve(3); const p2 = new Promise((resolve, reject) => { setTimeout(resolve, 100, 'foo'); }); const p3 = Promise.reject('出错了'); promiseAllSettled([p1, p2, p3]) .then(results => console.log(results)) .catch(error => console.error(error)); ``` ---