Unified SSR checking way

[lukeromanowicz]

What is the motivation for adding / enhancing this feature?

Currently, we are using multiple ways of checking if the code is running in SSR including:

• isServer in @vue-storefront/core/helpers
• typeof window === 'undefined'
• Vue.prototype.$isServer
• Passing though parameters i.e. in server registration
  and possibly others.

I suggest to use isServer from @vue-storefront/core/helpers as the only way to check the environment type as it is the easiest way to mock in tests and allows us to add some enhancements in the future if needed.

What are the acceptance criteria

• everywhere in the code we are using isServer in @vue-storefront/core/helpers as the way to check if the runtime environment is server or not
• isServer in module registration hooks is deprecated and shall throw logger.warn when reading its value. Should be removed in a couple of versions as redundant.

Can you complete this feature request by yourself?

Yes

[vue-kacper]

I agree

[pkarw]

Fixed in my PR: #2446

I need to change some other minor things and it will be ready the next week