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[英]How to get data from a promise (async/await) and use it `outside` the promise?
[英]How to get the result from other Promise with async await?
我尝试使用无服务器框架,目前我有2个文件:
我想先从server.js获取结果,然后再运行下一步。
我正在尝试使用await dan将结果保存到变量中,handler.js中的进程将同步运行,但startServer()结果未定义
// server.js
const mongoose = require('mongoose');
const dbHost = require('../config/keys').mongoURI;
module.exports = async () => {
mongoose.Promise = global.Promise;
mongoose.set('useFindAndModify', false);
return await mongoose
.connect(
dbHost,
{ useNewUrlParser: true }
)
.then(res => {
console.log('MongoDB Connected', res);
return res;
})
.catch(err => {
console.error(err);
console.error('MongoDB Not Connected');
return err;
});
};
// handler.js
const startServer = require('./db/server');
module.exports.hello = async (event, context) => {
let tryConnect = await startServer();
console.log('server is running', tryConnect);
return { statusCode: 200, body: JSON.stringify(tryConnect) };
};
如何从嵌套的async-await中正确地从await中获得结果?
谢谢
您可能只是返回await
后得到的值:
try {
const res = await mongoose.connect(dbHost, { useNewUrlParser: true });
console.log('MongoDB Connected', res);
return res;
} catch (error) {
console.error(err);
console.error('MongoDB Not Connected');
return err;
}
目前在没有必要的回调函数的mongoose.connect
如果您使用await
。 回调函数用于Promise
而不用于await
,请在async/await
使用try/catch
。
// server.js const mongoose = require('mongoose'); const dbHost = require('../config/keys').mongoURI; module.exports = async () => { mongoose.Promise = global.Promise; mongoose.set('useFindAndModify', false); return await mongoose .connect( dbHost, { useNewUrlParser: true } ); }; // handler.js const startServer = require('./db/server'); module.exports.hello = async (event, context) => { let tryConnect = {}; try { tryConnect = await startServer(); console.log('MongoDB Connected', tryConnect); } catch (err) { console.error(err); console.error('MongoDB Not Connected'); } console.log('server is running', tryConnect); return { statusCode: 200, body: JSON.stringify(tryConnect) }; };
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