ES7 的新功能 - async ... awite
但是在做 foreach 的時候卻碰到問題，我的觀念是 async 幫我做到平行處理的機制，
但是加上 foreach 後完全不是這麼回事...
詢問一下古哥，他幫我找到了這篇 Taming the asynchronous beast with ES7
他一樣有碰到 Loop 的問題
However, if you try to use an async function, then you will get a more subtle bug:
let docs = [{}, {}, {}];
// WARNING: this won't work
docs.forEach(async function (doc, i) {
await db.post(doc);
console.log(i);
});
console.log('main loop done');This will compile, but the problem is that this will print out:
main loop done
0
1
2
解法如下：
let docs = [{}, {}, {}];
let promises = docs . map (( doc ) => db . post ( doc ));
let results = [];
for ( let promise of promises ) {
results . push ( await promise );
}
console . log ( results );筆記...
