feat: adds support ReferencesMany relation

[mikeevstropov]

Definition in Model.

@referencesMany(() => Account)
accountIds: string[]; // or number[]

Include in query filter.

{"include": ["accounts"]}

Response will contain resolved relations in accounts field. E.g.

{
  "id": "customer-1",
  "accountIds": [
    "account-1",
    "account-2"
  ],
  "accounts": [
    {"id": "account-1", "balance": 10},
    {"id": "account-2", "balance": 20},
  ]
}

Related
#2488
#1450
#1920

Checklist

• DCO (Developer Certificate of Origin) signed in all commits
• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

[mikeevstropov]

Done

[coveralls]

Pull Request Test Coverage Report for Build 1940408176

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 257 of 300 (85.67%) changed or added relevant lines in 26 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.4%) to 76.409%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/repository/src/repositories/legacy-juggler-bridge.ts	2	3	66.67%
packages/repository/src/model.ts	0	2	0.0%
packages/repository/src/relations/references-many/references-many.decorator.ts	15	19	78.95%
packages/repository/src/relations/references-many/references-many.repository.ts	3	11	27.27%
packages/repository/src/relations/references-many/references-many.accessor.ts	11	20	55.0%
packages/repository/src/relations/references-many/references-many.helpers.ts	23	32	71.88%
examples/references-many/src/index.ts	4	14	28.57%

Totals
Change from base Build 1937893134:	0.4%
Covered Lines:	17144
Relevant Lines:	18024

---

💛 - Coveralls

[edgency]

Looks like no one needs this add-on, sadness

[achrinza]

Generally LGTM 👍 Will see if any of the other maintainers have any objection.

[mikeevstropov]

Redundant property itemType has been removed from the relation decorator. Example updated.

[achrinza]

Thanks, @mikeevstropov. I'll try to set some time to review the latest changes soon.

[dhmlau]

@mikeevstropov, your PR is almost good to go. Could you please squash the commits, esp the ones with Merge branch master...? Thanks.

cc @achrinza

[mikeevstropov]

@dhmlau Hi. I'm not sure if I did it right, just squashed the commits into one (including "merge" commits).

[dhmlau]

@mikeevstropov, hm.. as you pointed out, it has the merged commits, so doesn't look quite right.
I git clone your repo and noticed that you didn't set the upstream. Here is what I normally do to rebase community PRs:

git remote add upstream https://github.com/loopbackio/loopback-next.git
git remote -v // optional - used to verify remotes you have setup
git fetch upstream
git rebase -i upstream/master 
git push origin +references-many-relation

The caveat is... I'm not sure if the commands above could fix where we're at. (I tend to make another local copy of the changes before pushing again, because there're quite a lot of changes in this PR). Please give it a try. Hope it works! Thanks.

[achrinza]

@mikeevstropov It seems like most of the changes are localised in the @loopback/repository and @loopback/example-references-many packages. You can select only those specific set of files:

gitCommitHash="$(git log -1 --pretty=%H)"

# Take note of the hash in case you need to reset back to the current state:
echo "$gitCommitHash"

git reset --hard master

git checkout "$gitCommitHash" -- \
    packages/repository/src \
    examples/references-many \
    docs/site/MONOREPO.md \
    docs/site/Relations.md \
    docs/site/Relation-generator.md \
    docs/site/ReferencesMany-relation.md

git status # See the staged files

git commit -s

The above commands should cherry-pick all of the files needed. Please confirm everything is in order before doing a git commit -s and pushing it as this is a destructive action to the Git History. You can also choose to checkout these changes to a new branch and create a new PR.

In case of a SNAFU, we can get back to this current state by resetting back to the original hash:

git reset --hard "$gitCommitHash"

As a safety net, me (and I assume @dhmlau as well) have a local copy of this PR in its current state on our machines.

If you're not comfortable with this, the maintainers can help make the necessary changes from our end.

--

As for the commit message itself, as suggestion may be:

feat(repository): support `ReferencesMany` relation

closes: https://github.com/loopbackio/loopback-next/issues/2488

[achrinza]

#8455 is my attempt at "recovering" the original PR using the steps above. If it looks correct, you can try the above steps against this PR, or we can use that new PR if that's preferred.

[mikeevstropov]

@dhmlau @achrinza Sorry, got it, the PR should not contain the merged commits. It's fixed now.

[mikeevstropov]

@achrinza The commit is renamed as you suggest.

[achrinza]

Thanks for your contributions, @mikeevstropov! They have been merged 🎉