visitBlock() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/BuildReactiveFunction.ts lines 205–892

  visitBlock(block: BasicBlock, blockValue: ReactiveBlock): void {
    CompilerError.invariant(!this.cx.emitted.has(block.id), {
      reason: `Cannot emit the same block twice: bb${block.id}`,
      loc: GeneratedSource,
    });
    this.cx.emitted.add(block.id);
    for (const instruction of block.instructions) {
      blockValue.push({
        kind: 'instruction',
        instruction,
      });
    }

    const terminal = block.terminal;
    const scheduleIds = [];
    switch (terminal.kind) {
      case 'return': {
        blockValue.push({
          kind: 'terminal',
          terminal: {
            kind: 'return',
            loc: terminal.loc,
            value: terminal.value,
            id: terminal.id,
          },
          label: null,
        });
        break;
      }
      case 'throw': {
        blockValue.push({
          kind: 'terminal',
          terminal: {
            kind: 'throw',
            loc: terminal.loc,
            value: terminal.value,
            id: terminal.id,
          },
          label: null,
        });
        break;
      }
      case 'if': {
        const fallthroughId =
          this.cx.reachable(terminal.fallthrough) &&
          !this.cx.isScheduled(terminal.fallthrough)
            ? terminal.fallthrough
            : null;
        const alternateId =
          terminal.alternate !== terminal.fallthrough
            ? terminal.alternate
            : null;

        if (fallthroughId !== null) {
          const scheduleId = this.cx.schedule(fallthroughId, 'if');
          scheduleIds.push(scheduleId);
        }

        let consequent: ReactiveBlock | null = null;
        if (this.cx.isScheduled(terminal.consequent)) {
          CompilerError.invariant(false, {
            reason: `Unexpected 'if' where the consequent is already scheduled`,
            loc: terminal.loc,
          });
        } else {
          consequent = this.traverseBlock(
            this.cx.ir.blocks.get(terminal.consequent)!,
          );
        }

        let alternate: ReactiveBlock | null = null;
        if (alternateId !== null) {
          if (this.cx.isScheduled(alternateId)) {
            CompilerError.invariant(false, {
              reason: `Unexpected 'if' where the alternate is already scheduled`,
              loc: terminal.loc,
            });
          } else {
            alternate = this.traverseBlock(this.cx.ir.blocks.get(alternateId)!);
          }
        }