Listen to global filter

[indykoning]

the filter function isn't actually being listened to unless it is directly passed to the search function.

This PR updates that, to listen to the global filter function unless it is overwritten in the searchOptions passed to the function.

[lucaong]

Hi @indykoning,
thanks for your contribution!

It should be already possible to specify a filter "globally", like any other search option:

const miniSearch = new MiniSearch({
  fields: [/* list of fields... */],
  searchOptions: {
    filter: myFilterFunction
  }
})

// This will use the "global" filter specified above
miniSearch.search("something")

Is this what your PR meant to do? I prefer to keep search options separate from other options, but they can still be specified globally.

[indykoning]

Yes, the option to define the filter globally is indeed there.
however at
https://github.com/lucaong/minisearch/pull/282/files#diff-2ad78fe99a99053e4b46dc8136b24aecedd1a4ff6c4596409821cbb5f3b1e6deL1347

only the passed searchOptions are checked, so the global option isn't actually used.

This PR currently fixes that by merging the passed options over top of the global options.

If that isn't the preferred way I can also update the pr to work the same way as BoostDocument is handled.

[lucaong]

Oh you’re absolutely right, thanks for the bugfix! I will merge it as soon as I have time (I want to add a test to protect from regressions)

[lucaong]

I would also add a test, something like:

// This can go right after it('allows custom filtering of results on the basis of stored fields')
it('allows to define a default filter upon instantiation', () => {
  ms = new MiniSearch({
    fields: ['title', 'text'],
    storeFields: ['category']
    searchOptions: {
      filter: ({ category }) => category === 'poetry'
    }
  })
  ms.addAll(documents)

  const results = ms.search('del')
  expect(results.length).toBe(1)
  expect(results.every(({ category }) => category === 'poetry')).toBe(true)
})

[indykoning]

I've added the test as well 🙂

[lucaong]

Thanks a lot @indykoning ! This fix is part of release v7.1.1, which was just published on NPM