add support for hooks functions, setting query from URL, search exclusion

[bobheadxi]

• Add support for external results, which opens the result in a new tab
• Add support for functions, which provides an implementable interface for various hooks:
  • processSuggestions to augment, adjust, or manipulate the suggestions
  • onGoToSuggestion to perform actions whenever a result is clicked
• Add support for the fontmatter property search: false to exclude a page from results
• Add support for URL search parameter query for populating and focusing the search bar

[leo-buneev]

Thanks! That feature looks sweet, let's make it official.

I'd prefer to add more abstract hook processSuggestions(suggestions, queryString, queryTerms) in vuepress's settings, that will return new array of suggestions - can be useful for many scenarios, including yours.

Will be awesome if you'll find time to prepare it.

[bobheadxi]

@leo-buneev I'd be happy to - will update this PR and ping you with a nicer implementation 🚀

[bobheadxi]

@leo-buneev unfortunately, 5279837 is the only practical way to implement this API within the Vuepress plugin framework - let me know what you think! You can see one use case at ubclaunchpad/UBC-LAUNCH-PAD#84

Personally, I don't think it's too bad - vuepress still throws up fairly informative errors on syntax mistakes within the code. You could also do things like using readFileSync to provide the function string

[bobheadxi]

@leo-buneev I tried out the readFileSync approach in my usage of this branch (ubclaunchpad/UBC-LAUNCH-PAD#84) and it works very nicely - see bdfea2e for the updated docs:

const fs = require('fs');
const { path } = require('@vuepress/shared-utils');
module.exports = {
  plugins: [
    ['fulltext-search', {
      processSuggestions: fs.readFileSync(path.resolve(__dirname, 'processSuggestions.js')),
    }],
  ]
}

[leo-buneev]

Wow, that looks more complicated than I thought. Later today I'll try to implement option as a regular function (still can't believe it isn't possible 😮), and if I'll be unsuccessfull will merge your PR.
Thank you!

[bobheadxi]

Yeah I couldn't find a way to "persist" a user-provided function for callback :(

[bobheadxi]

@leo-buneev For our purposes I've expanded the API in fdeed1f to allow an onclick callback as well - I made the poor choice of opening the PR from a master branch, so please let me know if you would like me to make more granular PRs or just continue expanding on this feature in my fork :)

[leo-buneev]

Feel free to continue here, it can be considered as part of the same feature

[bobheadxi]

@leo-buneev any chance this might land one day? :) We've been running this in https://docs.ubclaunchpad.com with some non-trivial traffic for quite a while, and am quite content with the API defined here.

[bobheadxi]

@leo-buneev I've cleaned up the PR description and documentation!