WiP: Inline scope components

[barneycarroll]

Description

Add a new clause in the updateNode render loop which determines scope components to be equivalent if their source is identical.

Motivation and Context

The ability to declare a component inline allows for ad-hoc state capture without the rigmarole of breaking out to define a component elsewhere, determine what contextual reference access it needs, write the attrs interface accordingly, and then invoke it at call-site. In fact it facilitates iterative component development by enabling authors to experiment with component logic while benefiting from full call-site context reference access – leaving restrictive interface design as a formal 'ejection' exercise rather than a constant site of friction.

The internal logic determining equivalence relies on oldTag.toString() === tag.toString. Object and class components do not have as straightforward source-sniffing APIs, and the idiomatic style of OOP component-based application design means there is less benefit to the inter-scope access inline components provide.

How Has This Been Tested?

I've written a new test module but – strangely – these only pass if I run it alone, ie npm run test:js ./render/test-inlineComponent.js; maybe it's something to do with my slap-dash global Mithril instantiation at the top of the test file?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation change

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have updated docs/changelog.md