authoring-components

name

authoring-components

description

Guide for creating new Elements components with all required files, base classes, metadata patterns, and test boilerplate. Use this skill whenever the user wants to create, scaffold, or set up a new component from scratch, needs to understand the required 10-file structure, asks about base classes and mixins (LitElement vs ButtonFormControlMixin), define.ts vs index.ts patterns, static metadata, component registration, or sub-component parent relationships. Also trigger when the user mentions creating test boilerplate for all 5 test types.

Authoring Components

You MUST review the component creation guideline before creating or modifying components.

When to Use This Skill

• Creating a new component from scratch
• Understanding the required file structure for components
• Setting up test boilerplate for all 5 test types
• Choosing the appropriate base class or mixin (ButtonFormControlMixin vs LitElement)
• Understanding component metadata and registration patterns
• Setting up JSDoc comments for components

Must Read File

Read the component creation guide to get critical context for component creation guidance.

Workflow

1. Gather requirements: confirm the component name (kebab-case), purpose, and whether to use LitElement directly or apply ButtonFormControlMixin for button-like interactive components.
2. Study a reference: read the closest reference component listed below to understand the pattern in practice.
3. Create the 10 required files in projects/core/src/<component-name>/:
   • component-name.ts:component class with metadata, JSDoc, and render method
   • component-name.css:styles using CSS custom properties
   • component-name.examples.ts:example templates with @summary JSDoc
   • component-name.test.ts:unit tests
   • component-name.test.axe.ts:accessibility tests
   • component-name.test.visual.ts:visual regression tests
   • component-name.test.ssr.ts:SSR tests
   • component-name.test.lighthouse.ts:lighthouse tests
   • define.ts:registration using define() helper with HTMLElementTagNameMap
   • index.ts:side-effect-free export
4. Update shared entry points:
   • Add only import '@nvidia-elements/core/<component-name>/define.js' to projects/core/src/bundle.ts in alphabetical order. Keep this registration bundle import-only. Export the public API from the component index.ts and expose its entry point through the package exports map.
   • Add the definition import to the js-modules list in projects/core/src/index.test.lighthouse.ts so the combined direct-import benchmark measures the component.
5. Measure payloads: run mise exec -- pnpm run test:lighthouse from projects/core. Increase a bundle-size limit only when the measured payload exceeds the current limit.
6. Verify: confirm all files follow the templates in the component creation guide, then run mise exec -- pnpm run lint and mise exec -- pnpm run test from projects/core.

References

• Component Creation Guide - Complete component creation workflow
• TypeScript Guidelines - Type safety patterns
• Examples Guidelines - Example file structure
• Testing Guidelines - Testing strategy
• API Design - Properties - Property design patterns
• API Design - Styles - CSS custom properties

Reference Components

• /projects/core/src/button/ - ButtonFormControlMixin pattern example
• /projects/core/src/badge/ - LitElement pattern example
• /projects/core/src/card/ - Composition with slots example