Node JS + AWS Promise Triggered Twice

问题

AWS = require('aws-sdk');
AWS.config.region = 'eu-west-1';
ses = new AWS.SES();

var params = {};

return ses.sendEmail(params, function (err, data) {
    console.log('----->sending email')
}).promise().then((data) => {
    console.log('---->sending promise')
}).catch((err) => {
    console.log('----->am in error')
    console.log(err)
})

Can someone help my above code promise is triggered twice.

I should get below

----->sending email

---->sending promise

But i got

----->sending email

---->sending promise

----->sending email

回答1:

It looks like you are providing both a callback function and using the promise approach. Effectively, this means that you have two different functions that execute when the request is done. Choose one of the following:

You can use the promise approach, with then and catch.

function send(params) {
    ses.sendEmail(params).promise().then((data) => {
        console.log('Email was sent')
    }).catch((err) => {
        console.log('There was an error')
    })
}

You can use promise with async/await. Make sure you add the async keyword to your function header.

async function send(params) {
    try {
        const data = await ses.sendEmail(params).promise();
        console.log('Email was sent')
    } catch(err) {
        console.log('There was an error')
    }
}

Finally, you could use the callback approach:

function send(params) {
    ses.sendEmail(params, function(err, data) {
        if (err) {
            console.log('There was an error')
            return
        }
        console.log('Email was sent')
    })
}

来源：https://stackoverflow.com/questions/47635928/node-js-aws-promise-triggered-twice

标签

javascript

node.js

amazon-web-services

aws-sdk