Signup: Fix site path through domain-first flow

[drewblaisdell]

aca2949 updated flow-controller such that the redux store can be accessed in a step's apiRequestFunction via this._reduxStore, as apiRequestFunction is bound to the context of SignupFlowController which has a _reduxStore property.

This is a little bit fragile, as:

• It isn't clear which functions depend on the special context.
• Any function in StepActions that calls another function will need to use Function.prototype.call to preserve the this value.

I didn't catch this behavior when reviewing #10936, which broke the domain-first flow (which isn't public yet) if you select to create a site, as it called a function in StepActions without using .call to preserve the SignupFlowController context.

As far as I can tell, there isn't any reason to access reduxStore from the context instead of through a parameter, and doing the latter doesn't have the issues listed above. This PR makes that change.

Testing

• Visit /start/domain-first.

• Select a domain.

• Select to create a site in the second step.

• Proceed through the flow and assert that you land in checkout with the domain/plan you selected.

• Code

• Product

[matticbot]

Test live: https://calypso.live/?branch=fix/domain-first-with-site

[stephanethomas]

What do you think of using an arrow function here?

fetchSitesAndUser( siteSlug, () => {
	setThemeOnSite( addToCartAndProceed, { siteSlug, themeSlugWithRepo } );
} );

This may be just me but I find it more readable :).

[stephanethomas]

The code looks good - I only had a minor question.

However I've tested this pull request in an incognito tab several times but was sometimes redirected to the Plans page instead of the checkout (the shopping cart contained the right products though).

I have the feeling (maybe wrong) that there is a different behavior induced by some A/B tests : it worked fine every time I was presented with the option to upload a theme.

[drewblaisdell]

@stephanethomas Thanks for pointing that out. I was able to reproduce this by throttling to "Good 3G" in Chrome. Unfortunately, this affects master as well.

I added a commit to fix it, which was rather simple: ensure that we aren't setting the selected site in CartStore until the sites-list has fetched, as otherwise the cart is loaded for a siteless checkout and the user is redirected because that cart is empty.

[gziolo]

I noticed that we also have createSiteWithCartAndStartFreeTrial function that calls createSiteWithCart but reduxStore param is not passed. I have no idea if that is required, but we should double check if it doesn't break anything.

[gziolo]

I had one comment about missing reduxStore param which probably needs some action. Otherwise code changes look good 👍

[Tug]

@gziolo Addressed that, thx for noticing!
Code 👍

[Tug]

Product 👍