CollectPromotableTemporaries Class — react Architecture

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PromoteUsedTemporaries.ts lines 186–230

class CollectPromotableTemporaries extends ReactiveFunctionVisitor<State> {
  activeScopes: Array<ScopeId> = [];

  override visitPlace(_id: InstructionId, place: Place, state: State): void {
    if (
      this.activeScopes.length !== 0 &&
      state.pruned.has(place.identifier.declarationId)
    ) {
      const prunedPlace = state.pruned.get(place.identifier.declarationId)!;
      if (prunedPlace.activeScopes.indexOf(this.activeScopes.at(-1)!) === -1) {
        prunedPlace.usedOutsideScope = true;
      }
    }
  }

  override visitValue(
    id: InstructionId,
    value: ReactiveValue,
    state: State,
  ): void {
    this.traverseValue(id, value, state);
    if (value.kind === 'JsxExpression' && value.tag.kind === 'Identifier') {
      state.tags.add(value.tag.identifier.declarationId);
    }
  }

  override visitPrunedScope(
    scopeBlock: PrunedReactiveScopeBlock,
    state: State,
  ): void {
    for (const [_id, decl] of scopeBlock.scope.declarations) {
      state.pruned.set(decl.identifier.declarationId, {
        activeScopes: [...this.activeScopes],
        usedOutsideScope: false,
      });
    }
    this.visitBlock(scopeBlock.instructions, state);
  }

  override visitScope(scopeBlock: ReactiveScopeBlock, state: State): void {
    this.activeScopes.push(scopeBlock.scope.id);
    this.traverseScope(scopeBlock, state);
    this.activeScopes.pop();
  }
}