sf-b2b-lwc

name	sf-b2b-lwc
description	Build B2B Commerce LWC components — Lightning Web Components with @api/@track/@wire decorators, commerce-specific wire adapters, custom events, Lightning Web Security, Jest unit testing, and component lifecycle. Use when building B2B storefront UI components.
allowed-tools	Read, Write, Edit, Bash, Grep, Glob, WebSearch, WebFetch

sf-b2b-lwc

Build Lightning Web Components for Salesforce B2B Commerce storefronts.

Before Writing Code

Fetch live docs BEFORE writing code:

1. Web-search the latest:

   • "Salesforce Lightning Web Components Developer Guide 2026"
   • "Salesforce B2B Commerce LWC documentation 2026"
   • "lightning/commerce wire adapters 2026"
   • "Lightning Web Security LWC 2026"

2. Web-fetch official sources:

   • developer.salesforce.com/docs/component-library/documentation/en/lwc
   • developer.salesforce.com/docs/commerce/salesforce-commerce/guide/lwc-for-b2b.html
   • developer.salesforce.com/docs/platform/lwc/guide/reference-wire-adapters-intro.html

3. Verify current decorator syntax, commerce wire adapters, Jest testing patterns, and Lightning Web Security vs Locker behavior.

Conceptual Architecture

Component Structure (4 Parts)

File	Purpose	Notes
componentName.html	Template	{property} binding, lwc:if/lwc:else, for:each
componentName.js	Controller	ES6 class extending LightningElement, decorators, lifecycle hooks
componentName.css	Styles	Component-scoped, :host selector, CSS custom properties
componentName.js-meta.xml	Metadata	API version, targets (Experience Builder, App Builder), exposed properties

Decorators

Decorator	Purpose	Reactivity
@api	Public property (parent-settable) or public method	Re-renders on change from parent
@track	Deep reactivity for objects/arrays	Only needed for nested mutation (e.g., this.obj.nested = val)
@wire	Reactive data fetching from wire adapters	Re-fetches when reactive ($-prefixed) params change

Important: Primitive class fields are auto-tracked in modern LWC -- @track is only needed for deep object/array mutation. Reassigning the entire object triggers reactivity without @track.

Lifecycle Hooks

Hook	When	Use For
constructor()	Instance created	Initialize non-reactive state; cannot access DOM or properties
connectedCallback()	Inserted into DOM	Initialization, subscriptions (LMS, platform events)
renderedCallback()	After every render	DOM access; use sparingly (called frequently)
disconnectedCallback()	Removed from DOM	Cleanup listeners, unsubscribe channels, release resources
errorCallback(error, stack)	Child component error	Error boundary; log or display user-friendly messages

Wire Adapters

Wire adapters provide reactive, cached data fetching. Two binding styles exist:

• Property binding: @wire(adapter, params) propertyName; -- result is { data, error }
• Function binding: @wire(adapter, params) functionName({ data, error }) { ... } -- for custom handling

Commerce-specific adapters live under the lightning/commerce and commerce/* namespaces. Fetch live docs for the current list of available commerce wire adapters (products, pricing, cart, inventory).

// Pattern: Wire adapter usage
// Fetch live docs for adapter params
@wire(getProduct, { productId: '$productId' })
product;

Custom Events

Communication from child to parent uses CustomEvent:

Property	Purpose
detail	Event payload (keep minimal)
bubbles	Propagate up the DOM tree
composed	Cross shadow DOM boundary

Parent listens via on[eventname] attribute in template (all lowercase).

Component Communication Patterns

Direction	Mechanism
Parent to Child	@api properties set in parent template
Child to Parent	CustomEvent dispatched from child
Sibling / Unrelated	Lightning Message Service (LMS) via publish/subscribe

Security: Lightning Web Security (LWS)

LWS (default since Spring '23) replaces the legacy Locker Service:

• Native browser security via JavaScript sandboxing
• Shadow DOM enforcement for component isolation
• CSP (Content Security Policy) compliance
• Better performance than legacy Locker
• Supports modern browser APIs

Restrictions: No eval(), no Function(), no setTimeout(string). Use @salesforce/resourceUrl for static resources. Follow CRUD/FLS patterns for data access.

Experience Builder Integration

Components are exposed to Experience Builder via the js-meta.xml file:

• Set <isExposed>true</isExposed>
• Add lightningCommunity__Page and lightningCommunity__Default targets
• Define configurable <property> elements (String, Integer, Boolean, etc.)
• Properties appear in the Experience Builder property panel for drag-and-drop configuration

Jest Testing

LWC components are unit-tested with @salesforce/sfdx-lwc-jest. Key concepts:

• Mock wire adapters and Apex methods with jest.mock()
• Use createElement from lwc to instantiate components
• Access rendered DOM via element.shadowRoot.querySelector()
• Emit mock data from wire adapters; assert DOM changes after Promise.resolve()
• Clean up DOM in afterEach to avoid test pollution

// Pattern: Jest test skeleton
// Fetch live docs for mock utilities
import { createElement } from 'lwc';
import MyComponent from 'c/myComponent';

Best Practices

Data Fetching

• Use @wire for read-only data (reactive, cached via Lightning Data Service)
• Use imperative Apex for mutations (create, update, delete)
• Batch API calls to reduce server round-trips

Performance

• Minimize renderedCallback logic (runs on every render)
• Use getters for computed values (lazy evaluation)
• Debounce user input handlers
• Lazy-load large components via dynamic imports

Testing

• Write Jest tests for all components
• Mock wire adapters and Apex; test user interactions and error states
• Test accessibility: ARIA attributes, keyboard navigation

B2B Commerce Specific

• Respect buyer context (account, buyer group, entitlements)
• Handle guest vs authenticated experiences
• Display correct per-account pricing and product visibility
• Support multi-currency display in buyer's currency

Fetch the LWC Developer Guide, B2B Commerce LWC docs, and wire adapter reference for exact decorator behavior, adapter parameters, and testing utilities before implementing.