MyPromise

class MyPromise{constructor(executor){this.state='pending';this.value=undefined;this.reason=undefined;this.onFulfilledCallbacks=[];this.onRejectedCallbacks=[];// 绑定 this，确保 resolve/reject 中的 this 指向实例this.resolve = this.resolve.bind(this);this.reject = this.reject.bind(this);try {executor(this.resolve, this.reject);} catch (error) {this.reject(error);}}resolve(value){if(this.state==='pending'){this.state='fulfilled';this.value=value;this.onFulfilledCallbacks.forEach(callback=>{setTimeout(()=>{callback(this.value);},0)})}}reject(reason){if(this.state==='pending'){this.state='rejected';this.reason=reason;this.onRejectedCallbacks.forEach(callback=>{setTimeout(()=>{callback(this.reason);},0)})}}then(onfulfiled,onrejected){onfulfiled=typeof onfulfiled==='function'?onfulfiled:(value)=>value;onrejected=typeof onrejected==='function'?onrejected:(reason)=>{throw reason};return new MyPromise((resolve,reject)=>{const handleFulfilled=(value)=>{try{const result=onfulfiled(value);resolve(result);}catch(error){reject(error)}}const handleRejected=(reason)=>{try{const result=onrejected(reason);resolve(result);}catch(error){reject(error)}}if(this.state==='fulfilled'){setTimeout(()=>{handleFulfilled(this.value)},0)}else if(this.state==='rejected'){setTimeout(()=>{handleRejected(this.reason)},0)}else{this.onFulfilledCallbacks.push(()=>{setTimeout(()=>{handleFulfilled(this.value)},0)})this.onRejectedCallbacks.push(()=>{setTimeout(()=>{handleRejected(this.reason)},0)})}})}catch(onRejected){return this.then(null,onRejected);}finally(onFinally){return this.then(value => MyPromise.resolve(onFinally()).then(() => value),reason => MyPromise.resolve(onFinally()).then(() => { throw reason }));}static resolve(value) {if (value instanceof MyPromise) {return value;}return new MyPromise(resolve => resolve(value));};static reject(reason) {return new MyPromise(null,reject => reject(reason));};// 添加 all 方法
    static all(promises) {return new MyPromise((resolve, reject) => {if (!Array.isArray(promises)) {return reject(new TypeError('Argument must be an array'));}if (promises.length === 0) {return resolve([]);}const results = [];let completedCount = 0;promises.forEach((promise, index) => {MyPromise.resolve(promise).then(value => {results[index] = value;completedCount++;if (completedCount === promises.length) {resolve(results);}},reject);});});}// 添加 race 方法
    static race(promises) {return new MyPromise((resolve, reject) => {if (!Array.isArray(promises)) {return reject(new TypeError('Argument must be an array'));}promises.forEach(promise => {MyPromise.resolve(promise).then(resolve, reject);});});}
}