Transform Class — react Architecture

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/MergeReactiveScopesThatInvalidateTogether.ts lines 121–399

class Transform extends ReactiveFunctionTransform<ReactiveScopeDependencies | null> {
  lastUsage: Map<DeclarationId, InstructionId>;
  temporaries: Map<DeclarationId, DeclarationId> = new Map();

  constructor(lastUsage: Map<DeclarationId, InstructionId>) {
    super();
    this.lastUsage = lastUsage;
  }

  override transformScope(
    scopeBlock: ReactiveScopeBlock,
    state: ReactiveScopeDependencies | null,
  ): Transformed<ReactiveStatement> {
    this.visitScope(scopeBlock, scopeBlock.scope.dependencies);
    if (
      state !== null &&
      areEqualDependencies(state, scopeBlock.scope.dependencies)
    ) {
      return {kind: 'replace-many', value: scopeBlock.instructions};
    } else {
      return {kind: 'keep'};
    }
  }

  override visitBlock(
    block: ReactiveBlock,
    state: ReactiveScopeDependencies | null,
  ): void {
    // Pass 1: visit nested blocks to potentially merge their scopes
    this.traverseBlock(block, state);

    // Pass 2: identify scopes for merging
    type MergedScope = {
      block: ReactiveScopeBlock;
      from: number;
      to: number;
      lvalues: Set<DeclarationId>;
    };
    let current: MergedScope | null = null;
    const merged: Array<MergedScope> = [];
    function reset(): void {
      CompilerError.invariant(current !== null, {
        reason:
          'MergeConsecutiveScopes: expected current scope to be non-null if reset()',
        loc: GeneratedSource,
      });
      if (current.to > current.from + 1) {
        merged.push(current);
      }
      current = null;
    }
    for (let i = 0; i < block.length; i++) {
      const instr = block[i]!;
      switch (instr.kind) {
        case 'terminal': {
          // For now we don't merge across terminals
          if (current !== null) {
            log(
              `Reset scope @${current.block.scope.id} from terminal [${instr.terminal.id}]`,
            );
            reset();
          }
          break;
        }
        case 'pruned-scope': {
          // For now we don't merge across pruned scopes
          if (current !== null) {
            log(
              `Reset scope @${current.block.scope.id} from pruned scope @${instr.scope.id}`,
            );
            reset();
          }
          break;
        }
        case 'instruction': {
          switch (instr.instruction.value.kind) {
            case 'BinaryExpression':
            case 'ComputedLoad':
            case 'JSXText':
            case 'LoadGlobal':
            case 'LoadLocal':