```js function diPromiseAll(promises){ return new Promise((resolve, reject)=>{ // 參數判斷 if(!Array.isArray(promises)){ throw new TypeError("promises must be an array") } let result = [] // 存放結果 let count = 0 // 記錄有幾個resolved promises.forEach((promise, index) => { promise.then((res)=>{ result[index] = res count++ count === promises.length && resolve(result) // 判斷是否已經完成 }, (err)=>{ reject(err) }) }) }) } let p1 = Promise.resolve(1), p2 = Promise.resolve(2), p3 = Promise.resolve(3); diPromiseAll([p1, p2, p3]).then((res)=>{ console.log(res, 'res') }, (err)=>{ console.log(err, 'err') }) ```