Transform Class — react Architecture

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PropagateEarlyReturns.ts lines 126–337

class Transform extends ReactiveFunctionTransform<State> {
  env: Environment;
  constructor(env: Environment) {
    super();
    this.env = env;
  }

  override visitScope(
    scopeBlock: ReactiveScopeBlock,
    parentState: State,
  ): void {
    /**
     * Exit early if an earlier pass has already created an early return,
     * which may happen in alternate compiler configurations.
     */
    if (scopeBlock.scope.earlyReturnValue !== null) {
      return;
    }

    const innerState: State = {
      withinReactiveScope: true,
      earlyReturnValue: parentState.earlyReturnValue,
    };
    this.traverseScope(scopeBlock, innerState);

    const earlyReturnValue = innerState.earlyReturnValue;
    if (earlyReturnValue !== null) {
      if (!parentState.withinReactiveScope) {
        // This is the outermost scope wrapping an early return, store the early return information
        scopeBlock.scope.earlyReturnValue = earlyReturnValue;
        scopeBlock.scope.declarations.set(earlyReturnValue.value.id, {
          identifier: earlyReturnValue.value,
          scope: scopeBlock.scope,
        });

        const instructions = scopeBlock.instructions;
        const loc = earlyReturnValue.loc;
        const sentinelTemp = createTemporaryPlace(this.env, loc);
        const symbolTemp = createTemporaryPlace(this.env, loc);
        const forTemp = createTemporaryPlace(this.env, loc);
        const argTemp = createTemporaryPlace(this.env, loc);
        scopeBlock.instructions = [
          {
            kind: 'instruction',
            instruction: {
              id: makeInstructionId(0),
              loc,
              lvalue: {...symbolTemp},
              value: {
                kind: 'LoadGlobal',
                binding: {
                  kind: 'Global',
                  name: 'Symbol',
                },
                loc,
              },
            },
          },
          {
            kind: 'instruction',
            instruction: {
              id: makeInstructionId(0),
              loc,
              lvalue: {...forTemp},
              value: {
                kind: 'PropertyLoad',
                object: {...symbolTemp},
                property: makePropertyLiteral('for'),
                loc,
              },
            },
          },
          {
            kind: 'instruction',
            instruction: {
              id: makeInstructionId(0),
              loc,
              lvalue: {...argTemp},
              value: {
                kind: 'Primitive',
                value: EARLY_RETURN_SENTINEL,