Add support for res.cookie

[geritol]

res.cookie works in gatsby (eg. res.cookie("test", true, { httpOnly: false }) but does not work on netlify

Steps to reproduce

create a function that set a cookie eg.

export default function handler(req, res) {
  res.cookie("test", true, { httpOnly: false })
  res.redirect("/")
}

Expected behavior

runs and sets cookie locally.
on netlify the function is erroring with

Error when executing function "my-function.js": "res.cookie is not a function"

Can you submit a pull request?

Yes

[ascorbic]

Sounds good! If you want to open a PR I'm happy to look at it, otherwise I should be able to get to it in a couple of weeks

[geritol]

@ascorbic I am giving it a try right now.
I am not yet able to run tests yet.

Steps that I have figured out that I could not find documented in CONTRIBUTING.md:

• I needed to install dependencies in the plugin folder too
• I needed to install netlify-cli as a dev dependency to the root package

Currently the test command is filing with:

> function-test@1.0.0 build:netlify
> netlify build --offline

internal/modules/cjs/loader.js:834
  throw err;
  ^

Error: Cannot find module '@oclif/command'

Do you have any pointer what the issue could be?
I guess @oclif/command should be a dependency to netlify-cli

[geritol]

if I install netlify cli globally it fails with the following error

> function-test@1.0.0 build:netlify
> netlify build --offline

internal/modules/cjs/loader.js:834
  throw err;
  ^

Error: Cannot find module 'update-notifier'

[geritol]

Uninstalled a reinstalled netlify cli globally and it solved the above issue.
Now I am running into
There was a problem loading the local build command. Gatsby may not be installed. Perhaps you need to run "npm install"? Cannot find module 'date-fns/getDayOfYear'

[ascorbic]

Looking at the Gatsby docs, there is no mention of support for res.cookie(). It seems that because the dev server uses Express, those are supported by accident, but as this is not documented and may not work in production. For that reason I don't think we should add support.