如何在javascript中使模块异步

Question

我是JavaScript新手。我有使用sendgrid发送电子邮件的简单模块：

// using SendGrid's v3 Node.js Library 
// https://github.com/sendgrid/sendgrid-nodejs 
var helper = require('sendgrid').mail; 
var fromEmail = new helper.Email('test@test.com'); 
var toEmail = new helper.Email('sample@sample.com'); 
var subject = 'Sending with SendGrid is Fun'; 
var content = new helper.Content('text/plain', 'and easy to do anywhere, even with Node.js'); 


var mail = new helper.Mail(fromEmail, subject, toEmail, content); 

var sg = require('sendgrid')("**********************"); 
var request = sg.emptyRequest({ 
    method: 'POST', 
    path: '/v3/mail/send', 
    body: mail.toJSON() 
}); 

sg.API(request, function (error, response) { 
    if (error) { 
    console.log('Error response received'); 
    } 
    console.log(response.statusCode); 
    console.log(response.body); 
    console.log(response.headers); 
}); 

现在我想以异步方式调用此模块。我应该实现承诺还是使用异步，等待？

Answer 1

根据sendgrid的docs，承诺已经实现，这使得这更容易一些，因为你可以从模块中返回承诺。例如，如果你只是想用这个承诺，您可以：

//mymodule.js 

var helper = require('sendgrid').mail; 
var fromEmail = new helper.Email('test@test.com'); 
var toEmail = new helper.Email('sample@sample.com'); 
var subject = 'Sending with SendGrid is Fun'; 
var content = new helper.Content('text/plain', 'and easy to do anywhere, even with Node.js'); 



module.exports = function(from, subject, to, content){ 
    var mail = new helper.Mail(fromEmail, subject, toEmail, content); 

    var sg = require('sendgrid')("**********************"); 
    var request = sg.emptyRequest({ 
    method: 'POST', 
    path: '/v3/mail/send', 
    body: mail.toJSON() 
    }); 

    return sg.API(request) 
} 

现在，你可以简单地使用它像：

mail = require('./mymodule') 

mail("from@example.com", "subject", "to@example.com", content) 
.then(function(response) { 
    // use response.body etc 
})