All files / packages/fds-uif/generator-lwc/src/utils renderWhenPlan.ts

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import type {
  ComponentMetadata,
  ComposedComponentMetadata,
  RenderWhen,
  RenderWhenPropMatch,
  SlotMetadata,
  StructureMetadata,
} from '@fds-uif/generator-base';
import { uppercaseFirstChar } from './uppercaseFirstChar.js';
 
/**
 * Maps each node that carries a `renderWhen` clause to the LWC `lwc:if`
 * binding name used for it, plus the list of prop-equality getters that need
 * to be emitted on the class.
 */
export interface RenderWhenPlan {
  bindings: Map<StructureMetadata | ComposedComponentMetadata, RenderWhenBinding>;
  getters: PropEqGetter[];
}
 
export interface RenderWhenBinding {
  /** The expression to use inside `lwc:if={ ... }`. */
  expression: string;
}
 
export interface PropEqGetter {
  name: string;
  match: RenderWhenPropMatch;
}
 
const isSlot = (c: unknown): c is SlotMetadata => !!c && (c as SlotMetadata).type === 'slot';
 
const isComposed = (c: unknown): c is ComposedComponentMetadata =>
  !!c && (c as ComposedComponentMetadata).type === 'component';
 
/**
 * Build a render-when plan by walking the structure tree.
 *
 * - `'slotFilled'` is intentionally *not* recorded here: the analyzer already
 *   surfaces those at the parent via `node.conditionals` (which the template
 *   builder consumes directly).
 * - `'propFilled'` binds to the prop named in the node's first
 *   `boundAttributes` entry (or the node's `name` as a fallback).
 * - `{ prop, eq }` produces a synthesized getter named `is{Prop}{Eq}`.
 */
export function buildRenderWhenPlan(metadata: ComponentMetadata): RenderWhenPlan {
  const bindings = new Map<StructureMetadata | ComposedComponentMetadata, RenderWhenBinding>();
  const getters: PropEqGetter[] = [];
  const usedGetterNames = new Set<string>();
 
  const reserve = (preferred: string): string => {
    let name = preferred;
    let i = 2;
    while (usedGetterNames.has(name)) name = `${preferred}${i++}`;
    usedGetterNames.add(name);
    return name;
  };
 
  const consider = (node: StructureMetadata | ComposedComponentMetadata): void => {
    const rw = node.renderWhen as RenderWhen | undefined;
    if (!rw) return;
 
    if (rw === 'slotFilled') return;
 
    if (rw === 'propFilled') {
      const propName = inferPropFilledTarget(node);
      if (propName) {
        bindings.set(node, { expression: propName });
      }
      return;
    }
 
    // { prop, eq }
    const match = rw as RenderWhenPropMatch;
    const getterName = reserve(`is${uppercaseFirstChar(match.prop)}${pascalize(match.eq)}`);
    getters.push({ name: getterName, match });
    bindings.set(node, { expression: getterName });
  };
 
  const walk = (children: StructureMetadata['children'] | undefined): void => {
    if (!children) return;
    for (const child of children) {
      if (isSlot(child)) continue;
      consider(child);
      if (!isComposed(child)) walk(child.children);
    }
  };
 
  walk(metadata.structure.children);
 
  return { bindings, getters };
}
 
function inferPropFilledTarget(node: StructureMetadata | ComposedComponentMetadata): string | null {
  if (!isComposed(node)) {
    const ba = node.boundAttributes?.[0]?.prop;
    if (ba) return ba;
  } else {
    const bound = node.props?.bound;
    if (bound) {
      const first = Object.values(bound)[0];
      Eif (typeof first === 'string') return first;
    }
    const forwarded = node.props?.forwarded?.[0];
    if (forwarded) return forwarded;
  }
  // Last-ditch fallback: use the node's own name.
  return (node as StructureMetadata).name ?? null;
}
 
function pascalize(s: string): string {
  return s
    .split(/[-_\s]+/)
    .filter(Boolean)
    .map((seg) => uppercaseFirstChar(seg))
    .join('');
}