children method does not return duplicate children

[WeishenMead]

Calling node.children() does not always return duplicate children (instead it removes them). It looks like this is because children uses flatMap internally, and flatMap dedupes its entries.

Somewhat trivial test case:

render() {
  const foo = 'Foo';
  return (
    <div>
      {foo} Bar {foo} Bar {foo}
    </div>
  )
}

In this case I would expect:
node.children() === ['Foo', 'Bar', 'Foo', 'Bar', 'Foo']

but instead we get:
node.children() === ['Foo', 'Bar']

I tested this in version 2.9.1, but looking at the code I think it should still exist in master.

I think the right solution is to not use de-dupe in flatMap, but I'm not sure if there's a reason that was added in to begin with.

[ljharb]

Indeed, deduping in flatMap seems weird.

[ljharb]

Is this in shallow, mount, or both? Can you replicate it using v3?

[WeishenMead]

I replicated in shallow. I'll update the initial post with that. I haven't tried v3 (I took a quick look at the code and it seemed like this should still happen in v3 though).

I'll try to test with mount and see if it's there too.