If the approach is OK, I'll add to the docs

Looks good to me 🙂
Please go ahead and adjust the docs now 😉

And could you also add the same option tovue/singleline-html-element-content-newline as well please?

And could you also add the same option tovue/singleline-html-element-content-newline as well please?

I'm unsure how to do this, as a straight copy / paste of the changes into that rule doesn't quite work the same. For example, withignoreComments: true this test failes:

  valid:[{code:`      <template>        <div attr> <!-- comment --> </div>      </template>`,options:[{ignoreComments:true}]}]

with these errors:

  1) singleLineRule       valid      <template>        <div attr> <!-- comment --> </div>      </template>:      AssertionError [ERR_ASSERTION]: Should have no errors but had 2: [  {    ruleId: 'singleLineRule',    severity: 1,    message: 'Expected 1 line break after opening tag (`<div>`), but no line breaks found.',    line: 3,    column: 19,    nodeType: 'HTMLTagClose',    messageId: 'unexpectedAfterClosingBracket',    endLine: 3,    endColumn: 37,    fix: { range: [Array], text: '\n' }  },  {    ruleId: 'singleLineRule',    severity: 1,    message: 'Expected 1 line break before closing tag (`</div>`), but no line breaks found.',    line: 3,    column: 19,    nodeType: 'HTMLEndTagOpen',    messageId: 'unexpectedBeforeOpeningBracket',    endLine: 3,    endColumn: 37,    fix: { range: [Array], text: '\n' }  }]

But if I remove the whitespace around the comment:

  valid:[{code:`      <template>        <div attr><!-- comment --></div>      </template>`,options:[{ignoreComments:true}]}]

the test passes fine. I didn't see this issue in the multiline rule.

In this section of the rule code here:

if(ignoreWhenEmpty&&elem.children.length===0&&template.getFirstTokensBetween(elem.startTag,elem.endTag,getTokenOption).length===0){return}

I'm not sure why it's required to testelem.children.length === 0andgetFirstTokensBetween().length === 0—indeed, commenting that line out:

if(ignoreWhenEmpty&&// elem.children.length === 0 &&template.getFirstTokensBetween(elem.startTag,elem.endTag,getTokenOption).length===0){return}

then makes this valid:

<template><divattr><!-- comment --></div></template>`

but still reports errors for this:

<template><divattr> content<!-- comment --></div></template>`

I'm not sure why it's required to testelem.children.length === 0andgetFirstTokensBetween().length === 0

Probably it is indeed not needed, seems like both were added at the same time in#684. I guess if the other tests are passing, then removing theelem.children.length check should be fine.

Ah, this is a bit more complicated than I thought. Without my proposed changes, the default settings forsingleline-html-element-content-newline give these test results:

1. <div></div> → OK
2. <div> </div> → OK
3. <div attr></div> → OK
4. <div attr> </div> → Fail

I'm not sure if the behaviour here is really consistent—shouldn't 2 and 4 give the same result? Because the setting isignoreWhenNoAttributes and defaults totrue, I can't see a way to configure that case 4 passes the test. Is the only option here to just disable thesingleline-html-element-content-newline rule altogether?

It complicates my use case, as it's very common to put white space around comments, but then that white space counts as 'content':

<div attr><!-- comment --></div> → OK
<div attr> <!-- comment --> </div> → Fail

But I think that's OK, and is consistent with the existing rules / tests. I'll push an update with documentation for you to see.

It seems that the simple fix is also not working correctly formultiline-html-element-content-newline, seehttps://deploy-preview-2581--eslint-plugin-vue.netlify.app/rules/multiline-html-element-content-newline.html#ignorecomments-true:

<template><!-- should be good, but actually is reported because the div is now 2 line breaks below the template-->  <divclass="red"><!-- no error is reported here-->    content  </div></template>

So apparently a more elaborate logic is needed after all, probably that logic can then also be used for thesingleline-html-element-content-newline rule.