How do I promisify the AWS JavaScript SDK?

The 2.3.0 release of the AWS JavaScript SDK added support for promises: http://aws.amazon.com/releasenotes/8589740860839559

Way overdue, but there is a aws-sdk-promise npm module that simplifies this.

This just adds a promise() function which can be used like this:

ddb.getItem(params).promise().then(function(req) {
    var x = req.data.Item.someField;
});

EDIT: It's been a few years since I wrote this answer, but since it seems to be getting up-votes lately, I thought I'd update it: aws-sdk-promise is deprecated, and newer (as in, the last couple of years) versions of aws-sdk includes built-in promise support. The promise implementation to use can be configured through config.setPromisesDependency().

For example, to have aws-sdk return Q promises, the following configuration can be used:

const AWS = require('aws-sdk')
const Q = require('q')

AWS.config.setPromisesDependency(Q.Promise)

The promise() function will then return Q promises directly (when using aws-sdk-promise, you had to wrap each returned promise manually, e.g. with Q(...) to get Q promises).

I believe calls can now be appended with .promise() to promisify the given method.

You can see it start being introduced in 2.6.12 https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md#2612

You can see an example of it's use in AWS' blog https://aws.amazon.com/blogs/compute/node-js-8-10-runtime-now-available-in-aws-lambda/

let AWS = require('aws-sdk');
let lambda = new AWS.Lambda();

exports.handler = async (event) => {
    return await lambda.getAccountSettings().promise() ;
};

You can use a promise library that does promisification, e.g. Bluebird.

Here is an example of how to promisify DynamoDB.

var Promise = require("bluebird");

var AWS = require('aws-sdk');
var dynamoDbConfig = {
  accessKeyId: process.env.AWS_ACCESS_KEY_ID,
  secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
  region: process.env.AWS_REGION
};
var dynamoDb = new AWS.DynamoDB(dynamoDbConfig);
Promise.promisifyAll(Object.getPrototypeOf(dynamoDb));

Not you can add Async to any method to get the promisified version.