Index wikilinks in frontmatter strings

[Maarrk]

This implements #1000

The link is indexed only if it is the full content of a string node (allowing for quotes and whitespace) to discourage writing essays in the frontmatter 😄

I added an explanation why the quotes are needed on YAML page, I can't think of a page to document that the feature exists at all, I think it's discoverable by looking at indexPage in SETTINGS

[Maarrk]

Short demo of what it allows, credit to Raphwriter

[Maarrk]

Would be nice to make them clickable, but I think that becomes a much larger feature, since they shouldn't hide the [[ ]] like links in normal text do when cursor is away. Same for tags in frontmatter.

Considering #736 this would be almost like another editor mode when inside frontmatter: different widgets, different autocomplete etc., I don't know how I would approach that. Hope this bit here helps

[zefhemel]

I have this test page:

---
another: "[[nice page]]"
---
This is a nice page [[nice page]]!

```query
link where page = @page.name
```

I would expect 2 entries in link, one for the regular page link and one for the frontmatter. And sometimes I get this, but not always. I make a small edit, let it save and Alt-q and it's there, and sometimes it's not. Do you have any idea what could be going on here? Some sort of race condition?

Then, when I rename another page I would expect both these links to be updated, but that's also not happening. Perhaps it's related to this indexing not happening consistently though... Can you replicate this?

[Maarrk]

Funnily enough, it did work in a small test space, but in my main one, I can't get the frontmatter mention to show up at all. I will look into it more these days, thanks for the heads up 👍

[Maarrk]

Sorry for the delay, but the error was actually quite inconsistent to replicate. At the end I found it's a problem when reusing a Regex object with a global flag for multiple .exec() calls.

References:
https://stackoverflow.com/a/4724920/8531075
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastIndex

---

There are multiple places in the codebase with someImportedRegex.exec(text). When the const object is actually created is not obvious (at least for me). It's possible that every call site like this should have someImportedRegex.lastIndex = 0 before, for general reliability improvement. Recreating the Regex everytime makes more sense, but is probably slower.

[zefhemel]

Seems to work as advertised now. Thanks!

[zefhemel]

And interesting that these regexes are indeed stateful, I don't like that. It may indeed be better not to define them as globals in that case... Labeling them as const makes this even more confusing.