Stream depending on params for S3.getObject

[wawanco]

Hi there,

In my lib I have the following call

s3.getObject({ Bucket: bucket, Key: key }).createReadStream();

I would like to be able to mock to s3.getObject method and to have different stream depending on the key passed in parameter.

The kind of code I would like to write in my unit test is like

AWS.mock('S3', 'getObject', (params) => {
            if (params.Key === 'key1') {
                return 'body1';
            } else {
               return 'body2';
            }
});

Obviously it is not the way the lib work for now. Ideally I would have liked to have the following implementation of createReadStream in the mockServiceMethod method:

createReadStream() {
                const stream = new Readable();
                stream._read = function (size) {
                    if (typeof (replace) === 'string' || Buffer.isBuffer(replace)) {
                        this.push(replace);
                    } else if (typeof (replace) === 'function') {
                        this.push(replace(userArgs[0]));
                    }
                    this.push(null);
                };
                return stream;
            },

The part I want to add is if (typeof (replace) === 'function') {this.push(replace(userArgs[0]));}

Does it make sense to you ?