Error turning Amazon S3 function into promises using when/node

Question

I'm trying to lift an AWS S3 async function, and running into a weird error. Given the following code, ``` var s3 = new AWS.S3(); var when = require('when'); var nodefn = require('when/node'); var getObjectP = nodefn.lift(s3.getObject); getObjectP({ Bucket: 'bucket_name', Key: 'key_name' }) .then(function(data) { ... }, function(err) { ... }); ``` I get this error, ``` Object #<Object> has no method 'makeRequest' ``` Here's what the `getObject` looks like normally (it works fine when I use callbacks instead of promises): ``` s3.getObject({ ... }, function(err, data) { ... }); ``` Am I misusing `nodefn.lift`? It seems pretty straight-forward. Here's the docs for anyone interested. https://github.com/cujojs/when/blob/master/docs/api.md#nodelift

Accepted Answer

Probable the method has the wrong context, as it is not called as a method. Try to `bind` it:

```
var getObjectP = nodefn.lift(s3.getObject.bind(s3));
```

Error turning Amazon S3 function into promises using when/node

Solution

Problem