Vue: Fix format on self-closing and empty blocks

[fisker]

#9052 (comment)

• I’ve added tests to confirm my change works.
• (If changing the API or CLI) I’ve documented the changes I’ve made (in the docs/ directory)
• (If the change is user-facing) I’ve added my changes to changelog_unreleased/*/pr-XXXX.md file following changelog_unreleased/TEMPLATE.md.
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✨Try the playground for this PR✨

[fisker]

DO you guys think this is bug?

Prettier 2.1.0
Playground link

--parser vue

Input:

<custom lang="markdown"></custom>

Output:

<custom lang="markdown">

</custom>

[thorn0]

Yes, looks unexpected.

[sosukesuzuki]

I agree with thorn0

[fisker]

This one, html think it's not empty, and markdown will print to a empty Doc, how do I tell it's empty?

[thorn0]

The only child node is text consisting of whitespace only.

[fisker]

{
      "type": "concat",
      "parts": [
        {
          "type": "concat",
          "parts": [
            {
              "type": "fill",
              "parts": []
            }
          ]
        }
      ]
    }

[thorn0]

Try using normalizeParts from doc-utils. You might want to improve it to handle an empty fill doc.

[fisker]

What if the embed parser return ifBreak('foo', ''), we should not be able to know it's empty or not. Am I right?

[thorn0]

Can't we first check if the content of the tag is empty or whitespace-only and skip the embedded parser if it is?

[fisker]

I tried, and it works, just feel something not right.

[thorn0]

It's fine to assume that reformatting an empty document should result in an empty document for any language.

[fisker]

Done