Add ability to pass translation strings into accordion component via JS

[vanitabarrett]

What

Add ability for users to pass a translation object in via JavaScript (at the point of initialisation). This is an alternative method to passing translation strings via the Nunjucks macros (data-attributes).

Example:

new Accordion($element, {

  "i18n.showAllSections": "Show everything"

}).init()

Why

Some users may prefer to pass translation strings via JavaScript, or it may be better suited to their service.

Who needs to work on this

Developers

Who needs to review this

Developers

Done when

• It’s possible to provide translations to the accordion component via JavaScript
• Expanded logic which looks up translations passed via data attributes, to lookup translations provided by JavaScript
• Data attribute translations take priority over JS translations, if both provided
• The accordion component still works if no/only some translations are passed (falls back to defaults)
• The accordion component has tests which cover the ability to translate via JavaScript