Added filters page and link from how-tos

[vickytnz]

Filters page that:

• adapts the govuk prototype kit guidance for using or making filters https://prototype-kit.service.gov.uk/docs/filters and adapts to an earlier version of the kit (particularly for formatting html in filters)
• includes the guidance for dates using xgovuk filters https://prototype-kit.service.gov.uk/docs/date-filters by merging it into the same page

I have tried running this all locally and it seems to work.

Section in how-tos

Filters page

This page may be running long but i am positioning it for now as a way to understand filters. It could be that this gets split, however I also wonder if this shows that the filters part of the kit needs to get updated to make it in line with the current govuk kit.

[vickytnz]

How to page with basic information

Simplified page

[vickytnz]

Hmm after looking properly at the Nunjucks documentation for filters:

https://mozilla.github.io/nunjucks/api#custom-filters

I wonder if this page should get held back unpublished until we can update the filters page to properly work as documented in the guidance? Or I have to do a disclaimer that the documentation won't work which .... isn't great.

UPDATE: now understand how these connect and have updated guidance.

[vickytnz]

New version:

How-to page

Minor tweak to language

Page

Pretty big changes including:

• adding new example - not sure if this is overdocumented? Have also left it in the old style of filters for now but that can get changed to use arrows if needed
• note about how to translate the other filters like in the nujucks documentation to this kit - selfishly this is documentation I wish that I had up until now, however part of me is wondering if this should be split into an advanced page. I may have also run out of steam writing the documentation for that.

[vickytnz]

Arrgh I've realised that the docs kit doesn't have an up-to-date filters page so there is a lot of stuff there that I didn't know was there. Redoing the code examples based on the exact examples that are there.

[vickytnz]

New version:

How-to page

Minor tweak to language

Page

Now has

• example from existing file (with note to bring out of comments)
• example of sentence case filter (do wonder if this should just go in as an example really)
• note about how to translate the other filters like in the nujucks documentation to this kit - selfishly this is documentation I wish that I had up until now, however part of me is wondering if this should be split into an advanced page. I may have also run out of steam writing the documentation for that.

[sarawilcox]

Hi @vickytnz, re the page about filters. It feels very complex to me. I'm wondering whether we should have a basic usage section and an advanced usage section as GOV does: https://prototype-kit.service.gov.uk/docs/tutorials-and-guides. Perhaps with branching being advanced too? Did you consider this?

If we do keep it in for advanced users, I suspect that we need to explain in more detail what "filters" are here. It's taken me a while to work it out. I was thinking more about filters in the sense of filtering a list.

I can do a content review next week.