Prettyhtml should not put multiple tags into the same line

[octref]

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🐛 Bug Report

vuejs/vetur#1018
Related: prettier/prettier#5596

When user explicitly choose to put elements in multiple lines, prettyhtml should not put them in the same line (and break whitespace).

To Reproduce

Steps to reproduce the behavior: Format it in https://prettyhtml.netlify.com/

Paste your markup here:

<h1>
  404
  <template v-if="resource">
    the {{ resource }} was
  </template>
  not found
</h1>

Expected behavior

Whitespace is preserved.

Paste the results here:

<h1>
  404
  <template v-if="resource">
    the {{ resource }} was
  </template>
  not found
</h1>

Instead the result is:

<h1>
  404
  <template v-if="resource">the {{ resource }} was</template>not found
</h1>

which could render as "wasnot found" in the end.

Context

• Vue

Your Environment

Latest on https://prettyhtml.netlify.com.

[StarpTech]

Hi @octref thanks for the bug report. The current behavior is correct but this is tricky because the template tag isn't whitespace sensitive but when it will be replaced it will create a different result. I think we should add the template tag to the list so that the nodes are handled as not collapsable.

[octref]

That makes sense to me. Thanks!