Javascript: SyntaxError: await 仅在异步函数中有效

Gtting the following error when trying to use await.

SyntaxError: await 仅在异步函数中有效

代码:

async function addEvent(req, callback) {
    var db = req.app.get('db');
    var event = req.body.event

    db.App.findOne({
        where: {
            owner_id: req.user_id,
        }
    }).then((app) => {

                let promise = new Promise((resolve, reject) => {
                    setTimeout(() => resolve("done!"), 6000)

                })

               // I get an error at this point 
               let result = await promise;

               // let result = await promise;
               //              ^^^^^
               // SyntaxError: await is only valid in async function
            }
    })
}

得到以下错误:

               let result = await promise;
                            ^^^^^
               SyntaxError: await is only valid in async function

我做错了什么?

推荐答案

addEvent 是 async..await 和原始 promise 的混合体.await 是 then 的语法糖.它是一个或另一个.混合导致不正确的控制流；db.App.findOne(...).then(...) promise 没有被链接或返回，因此在 addEvent 外部不可用.

async function addEvent(req, callback) {
    var db = req.app.get('db');
    var event = req.body.event

    const app = await db.App.findOne({
        where: {
            owner_id: req.user_id,
        }
    });

    let promise = new Promise((resolve, reject) => {
        setTimeout(() => resolve("done!"), 6000)
    })

    let result = await promise;
}