fix(base-entity): set create return type to T[]

[merceyz]

What's the problem this PR addresses?

The version of BaseEntity.create that takes an array of entityLike objects returns an array of entities but the return type incorrectly specifies that it's a single entity.

How did you fix it?

Changed the return type from T to T[]

[pleerock]

Thanks!

[jalooc]

FYI this broke existing code in a way described in this issue: #1583 (comment)

tl;dr; this code:

const foo = Foo.create({ ...req.body }) // req.body is `any`
console.log(foo.bar)

suddenly breaks, because before the update foo used to be of Foo type and after the update it becomes Foo[] (note the array).

This might be TS fault instead TypeORM's fault, I'm not sure. But since it's breaking working code, it definitely requires a second look.

[sherbakovdev]

Same for me. This broke the existing code.

[Diluka]

I thought it was TypeScript(microsoft/TypeScript#37471), but turned out to be this.

[itsjbecks]

Has there been any update on this / more background on why this was changed. It also broke existing code on our project.

[Diluka]

@pleerock look here. this pr introduce a breaking change

[pleerock]

Type signature seems to be right. It expects an array and we get array back. I don't see how it can be wrong right now, can somebody point me what can be wrong ?

[jalooc]

@pleerock The code looks good, but its usage is crooked. The problem is that when using object spread operator in the create({ ...x }) argument, TS somehow thinks (probably because of some TS error) that this definition should be used, not that. Therefore doing something like this: const y = Model.create({ ...y }) makes y of type Model[] instead of Model, which was not the case before this PR. So while what you wrote here seems totally logical, it does not work this way.

[pleerock]

okay, but this PR definitely fixes issue. Not sure how can I help with particular this use case when you use any object.