Support latest handler arguments, callback

[samdj]

Currently I have to set the callback as so:

export function handler(event, context, done) {
    done = done || context.done

    return done(null, {
        message: 'Go Serverless! Your Lambda function executed successfully!'
    })
}

Apparently the new lambda API encourages use of the 3rd optional callback.

May be worthwhile for normalizing: https://github.com/SC5/lambda-wrapper

[thenikso]

I wasn't aware of that lambda-wrapper project. I'll give it a look at some point.

What actions should be taken on this @samdj ?

[samdj]

I'll do some testing to see whether this is node43 related and whether the lambda wrapper is necessary.

[samdj]

@thenikso I can confirm we need to use the lambda-wrapper. The third argument needs to be set under node4.3.

[thenikso]

would it make sense to use the 3rd argument as the callback directly? We're already doing so in https://github.com/elastic-coders/serverless-webpack for serverless 1.0