Start expanding the library's public API

[romaricpascal]

Brief

Start expanding the public API of GOV.UK Frontend by opening some features for initialising components:

• checking if GOV.UK Frontend is supported in a consistent way
• initialising GOV.UK Frontend components and service components the same way
• offering a base component class checking GOV.UK Frontend support and storing the root element of components

Ensure these features are documented in the Frontend docs, with both:

• guidance on how to use them
• an API reference of the classes/functions that provide them (and their properties/methods/arguments/return values...)

This is a first step towards maintaining a wider public API both for using our components and creating components in services.

Epic lead

@romaricpascal

Driving role(s)

@seaemsi, @patrickpatrickpatrick

Supporting roles

Needs awareness

Further detail

Expanding the API

Beta Give feedback

1. Investigate impact on types and TypeScript of our plans for createAll #5209
   javascript +1
   
2. Make isSupported() part of our public API #5210
   javascript +1
   
3. Add leading check to verify that GOV.UK Frontend is supported in createAll #5213
   javascript +1
   
4. Update JavaScript components of the Design System website so they can be used with the createAll function govuk-design-system#3812
   javascript +1
   
5. Allow createAll to initialise components not provided by GOV.UK Frontend #5211
   javascript +1
6. Add callback to respond to errors when a component does not initialise in createAll #5212
   javascript +1
   
7. Make a base class for people to build components with part of our public API #5214
   javascript +1
8. [Stretch] Investigate components being initialised more than once #1127
9. Add callback to respond to errors when a component does not initialise in initAll #5267
   +0
   
10. [Stretch] Investigate how to initialise multiple components on a single element #5216
    javascript +1
11. [Strech] Investigate how to initialise components that do not require root elements #5217
    javascript +1
12. [Stretch] Investigate how to prevent component initialisation based on a condition #5225
    javascript +1
    
13. [Descoped for now] Allow to initialise multiple components in a single call #5215
    javascript +1

Documenting the API

Beta Give feedback

1. List pieces of documentation matching the API features we imagined in previous cycle #5224
   documentation +1
   
2. Figure the best place for documentation to go in the existing docs govuk-frontend-docs#462
   documentation +1
3. Automatically generate API reference in Frontend docs #5227
   documentation epic javascript +3
4. Add documentation for isSupported to the Frontend docs
5. Add documentation for the updates to createAll to the Frontend docs
6. Add documentation for the base component class to the Frontend docs

Admin

Beta Give feedback

1. Initialise decision log (based on Navigation one)
2. Document the state we aim for at the end of the cycle

[romaricpascal]

Work will carry on in #5292