Better support for Serverless Framework

[dbryantm]

Reduces the size even further for projects that are using the Serverless Framework while bundling functions individually for AWS Lambdas. Otherwise it seems to still be bundling all of lodash even if the project doesn't require it.

[coveralls]

Coverage remained the same at 100.0% when pulling 46900aa on dbryantm:feature/serverless-bundling into ea75ed0 on frankthelen:master.

[Hakuz]

To make the size more smaller, what about removing the bluebird with es6 native promise?

[dbryantm]

I wouldn't disagree with that. I also think it wouldn't be a bad idea to move to using Babel so you can use imports and tree shaking. Some of the changes would be breaking enough that the maintainer would need to make those decisions though.

[frankthelen]

Yes, Bluebird could be removed without breaking anything, I think. I'll check it. Thanks.

[frankthelen]

@Hakuz @dbryantm
I removed Bluebird in favour of native promises (#30). Please review. All tests are green with Node 8/10/11.

[dbryantm]

Merged the new version of master into the feature branch.

[dbryantm]

@frankthelen, any chance you could review this? Thanks in advance!

[frankthelen]

Honestly, requiring lodash's individual method packages is an antipattern. In addition, they are not maintained anymore (deprecated). Rools depends on the main library, but requires individual packages, e.g., const intersection = require('lodash/intersection');. As far as I understand, this is exactly the way it should be done. And also should allow for tree shaking (which I haven't tried yet).

[dbryantm]

The only way to achieve tree shaking successfully with lodash is to use lodash-es instead and just require the individual functions such as:
const intersection = require('lodash-es/intersection'); or import { interesection } from 'lodash-es';.
There's some threads actually out there regarding this issue with webpack, such as webpack/webpack#6925 (comment). I think at least making that change would be a step in the right direction. Thoughts?

Also, I'd be glad to make those changes in another pull request if you would be willing to review it. Thanks in advance!

[frankthelen]

Unfortunately, on the Node side, ES modules are still flagged experimental, even in Node 10. And since Rools is supporting Node >= 8, this does not look like an option to me. Maybe we should eliminate lodash altogether. What Rools is using from it (intersection, isBoolean, isFunction, isInteger, isString) could easily also be achieved differently without lodash.

[frankthelen]

We could use https://www.npmjs.com/package/is for the validators.

[dbryantm]

Yeah, that could possibly work though I would like to see the size of the library when it gets bundled with webpack. I could try some tests to see what the end results are.

[jonioni]

Lodash is now discouraging the use of per method packages (reference). With webpack5 wondering if this issue is still present? @dbryantm