es7 support

[andrzejewsky]

Related issues

related vuestorefront/vue-storefront-api#342

Which environment this relates to

• Test version (https://test.storefrontcloud.io) - this is a new feature or improvement for Vue Storefront. I've created branch from develop branch and want to merge it back to develop
• RC version (https://next.storefrontcloud.io) - this is a stabilisation fix for Release Candidate of Vue Storefront. I've created branch from release branch and want to merge it back to release
• Stable version (https://demo.storefrontcloud.io) - this is an important fix for current stable version. I've created branch from hotfix or master branch and want to merge it back to hotfix

Upgrade Notes and Changelog

• No upgrade steps required (100% backward compatibility and no breaking changes)
• I've updated the Upgrade notes and Changelog on how to port existing VS sites with this new feature

Contribution and currently important rules acceptance

• I read and followed contribution rules

[pkarw]

@andrzejewsky yeah, exactly this. But it should be conditional statement to support prev. Elastic versions as well

[pkarw]

I'd suggest just to check if total.value doe exist or if total is an object - we shouldn't prefferably have an additional config variable just for that

[andrzejewsky]

@pkarw done

[ajsit]

You havnt addressed the breaking changes issue for Elastic 7, _sourceInclude and _sourceExclude is deprecated and requires the plural form now.

[andrzejewsky]

@ajsit we are still working on ES7 integration, planned to be released in 1.11. This PR fixes common issues that we've found, but the PR that introduces ES7 in the API has not merged yet as it requires more tests. When it comes to breaking changes - we'd like to support both ES5 and ES7 without BC-breaks for end user/developer as it could be possible so probably these name for VSF perspective will be still same - will see, otherwise we put some upgrade notes.

Thanks for comment 👍