feat(getTagContentType): add `prefix` and `hasParent` parameters

[ikatyang]

Context: https://github.com/ikatyang/angular-html-parser/issues/11#issuecomment-620560801

This PR adds two parameters for getTagContentType so that Vue SFC could be correctly parsed:

• prefix: the namespace
• hasParent: determine if it's a root element

The implementation for hasParent is a bit hacky, it

• initializes a stack to record tag names,
• push the tag name to the stack once it meets a root open tag or a open tag with the same tag name as the root tag,
• pop the tag name once it meets the corresponding close tag, and
• hasParent is considered true if the stack is empty at the moment.

The reason why I implemented it this way is that I don't want to duplicate the entire parsing process in the lexer, though there are some drawbacks for the current implementation:

• void tags won't work if they are root elements
• tags with special rules won't work if they are root elements, for example:
  • <li> could be closed by a sibling <li> but it won't work if it's a root element
  • <tr> could be closed by a parent </tbody> but it won't work if it's a root element
• htm closing tags (<//>) won't work if they are root elements or their names are the same as the root element

But I think it should be fine for the Vue SFC parsing since no one would encounter these edge cases in real life IMO.

This PR also contains a test case for Vue SFC parsing.

cc @fisker @thorn0 @sosukesuzuki

[fisker]

Seems there is no attribute info, so will this work?

<template lang="pug">
  #container
    some-component(tag='<some-tag>')
</template>

[ikatyang]

I've checked vuejs/vue-next:

https://github.com/ikatyang/angular-html-parser/issues/11#issuecomment-621613078

And also I've checked that <template lang="something-else"> is parsed just like normal <template>s, which means we don't need additional information (e.g., attributes) to distinguish them.

[fisker]

Okay, good know, thanks.

[ikatyang]

👉 https://github.com/ikatyang/angular-html-parser/releases/tag/v1.6.0