在foreach循环中异步

Question

我需要在foreach中的每个异步方法结束时返回值。

我该怎么做？

 return backupModel.find({}).exec().then(backups => {
        backupBuild = []
        backups.forEach((backup, i) => {
            userDB.getC(backup.id).then((user) =>{
                backupBuild[i].client=user
            })
        })
        return backupBuild,
    });

Answer 1

尝试Promise.all：

return backupModel.find({}).exec().then(backups =>
    Promise.all(backups.map(backup => userDB.getC(backup.id)))
).then(backupBuild => console.log(backupBuild));

Answer 2

我也试过了：但是＆＃34;无法设置属性＆＃39;客户端＆＃39;未定义＆＃34;

return backupModel.find({}).exec().then(backups => {
    let backupBuild = [];
    let promises = [];
    backups.forEach((backup, i) => {
        promises.push(userDB.getCustomer(backup.idClient).then((user) =>{
            backupBuild[i]= backup;
            backupBuild[i].client= user;
        }))
    })
    Promise.all(promises).then(() => {return console.log(backupBuild)})
});