Define and create new content needed for v5.0.0 of GOV.UK Frontend

[claireashworth]

What

Define what changes are needed to update our content for v.5.0.0 of GOV.UK Frontend and draft content.

Why

v5.0.0 might need explicit documentation to differentiate it from v4.0.0.

Who needs to work on this and review it

Tech writer, content designer, developers, designers

Done when

The content is agreed and drafted ready for testing with users and reviewing.

• Use plans from #3549 to define what needs to be in documentation for v5.0.0
• Write draft documentation for v5.0.0
• Review complete
• Final amendments before publishing

[claireashworth]

Content changes identified to date:

Frontend Site

Landing page

• clarify the line ‘use GOV.UK Frontend with old (‘legacy’) GOV.UK frameworks’
• add another line about using previous versions of frontend
• potentially move some of the initial ‘get started’ info to this page in preparation for amending that section (maybe a name change to something like ‘Setting up GOV.UK Frontend’)
  Install with Node.js package manager (npm)
• check whether the requirements need updating
• check whether the install instructions need updating
  Install using precompiled files
• check whether package install is correct and update link as needed
• update the ‘cannot do after installing’ information. This could potentially include some relevant info about v4/v5 differences with a link to a new page on the differences if we go that route
• [from Ollie] update the example HTML to update the inline script and to remove the IE8 specific stylesheet
• [from Ollie] update the example in step 3 of ‘copy the files’ to remove the crown png reference
• [from Ollie] - In Get started step 5 ('Get the JavaScript working') - the inline script in step 1 will need updating and Step 3 will need updating (to use type="module", I think?)
  Update using Node.js package manager (npm)
• update example where it shows version “4.5.0”
• update earlier versions example?
• would this work better if moved next to the Installing npm section?
  Support Internet Explorer 8
• [from Ollie] - This page will need to be removed
  Use with our old frameworks or colours
• [from Ollie] - This page will need to be removed
  Using HTML test files
• Check if the file structure change means this section needs updating with different file paths
  Migration from our old frameworks
• [from Ollie] - This page will need to be removed
• This page to be replaced with a new page about migrating to v5 and highlighting the differences between v4 and v5 for reference
  Import CSS, assets and JavaScript
• [from Ollie] 'Import JavaScript using a bundler' might change
• [from Ollie] The CSP hash for the inline script will have changed in v5
• [from Ollie] 'Select and initialise an individual component' might change if we create a static function to instantiate new components
  Configure components with JavaScript
• [from Ollie] 'Passing configuration to a new instance of a component in JavaScript' might change if we create a static function to instantiate new component
  Javascript API reference
• [from Ollie] The example at the top of the document (set the preventDoubleClick option of a button) might change
  Sass API reference
• [from Ollie] The entry for $govuk-new-link-styles will no longer exist after v5, but needs to remain for v4

[claireashworth]

The 2 main pieces of content left to do are:

• the new page recorded in issue Create a new page highlighting v5 differences and how to migrate to v5 #315 (which will probably be completed in a separate PR)
• the 'undecided' elements discussed with the developers

[Izabela-16]

Ollie to look at documenting it on Friday, so Claire is clear what solution will be used.