Added sockHost, changed how sock URL is built

[knagaitsev]

• This is a bugfix
• This is a feature
• This is a code refactor
• This is a test update
• This is a docs update
• This is a metadata update

For Bugs and Features; did you add new tests?

Yes

Motivation / Use-Case

As mentioned here: #1777, there could potentially be a need for a sockHost which is different from the host option.

I also realized that when sockPort was added, a problem could occur if sockPort was included but sockPath was not. Specifically, they both check urlParts.path === '/' to see if the query string should be parsed or not, but that method of checking only works if a single option is passed in through urlParts.path. I can make a minimum reproducible test repo for this problem if needed. This is the reasoning behind partially changing how the sock url is built.

Breaking Changes

None

Additional Info

[hiroppy]

Please use strict equality operator. Or are you intentionally doing so to include undefined?

[knagaitsev]

That's how it was here: https://github.com/webpack/webpack-dev-server/blob/master/client-src/default/index.js#L235. I kept it that way under the assumption that it might need to catch undefined.

[hiroppy]

I see. I didn't know that it was already used...

[alexander-akait]

@Loonride i think we should fix using != (==` and etc) in our code base

[knagaitsev]

@evilebottnawi should I fix it here?

[hiroppy]

I want to change !==, but its change is the breaking change, so please rewrite as below.

if ((urlParts.path !== null || urlParts.path !== undefined) && urlParts.path !== '/') {

[knagaitsev]

I think urlParts.path != null would turn into (urlParts.path !== null && urlParts.path !== undefined)

[hiroppy]

You're right. My mistake.

[hiroppy]

I think we don't have to write explicitly.

[knagaitsev]

You mean the "type": "null"? The host option has the same format.

[hiroppy]

Yes, we discussed here, and I also don't think it's necessary.

fyi: webpack/webpack.js.org#2995 (comment)

[alexander-akait]

Very good job, one note above

[hiroppy]

lgtm