getTag: switch()

in packages/react-reconciler/src/ReactFiber.old.js [497:593]
89 lines of code
35 McCabe index (conditional complexity)

    getTag: switch (type) {
      case REACT_FRAGMENT_TYPE:
        return createFiberFromFragment(pendingProps.children, mode, lanes, key);
      case REACT_STRICT_MODE_TYPE:
        fiberTag = Mode;
        mode |= StrictLegacyMode;
        if (enableStrictEffects && (mode & ConcurrentMode) !== NoMode) {
          // Strict effects should never run on legacy roots
          mode |= StrictEffectsMode;
        }
        break;
      case REACT_PROFILER_TYPE:
        return createFiberFromProfiler(pendingProps, mode, lanes, key);
      case REACT_SUSPENSE_TYPE:
        return createFiberFromSuspense(pendingProps, mode, lanes, key);
      case REACT_SUSPENSE_LIST_TYPE:
        return createFiberFromSuspenseList(pendingProps, mode, lanes, key);
      case REACT_OFFSCREEN_TYPE:
        return createFiberFromOffscreen(pendingProps, mode, lanes, key);
      case REACT_LEGACY_HIDDEN_TYPE:
        if (enableLegacyHidden) {
          return createFiberFromLegacyHidden(pendingProps, mode, lanes, key);
        }
      // eslint-disable-next-line no-fallthrough
      case REACT_SCOPE_TYPE:
        if (enableScopeAPI) {
          return createFiberFromScope(type, pendingProps, mode, lanes, key);
        }
      // eslint-disable-next-line no-fallthrough
      case REACT_CACHE_TYPE:
        if (enableCache) {
          return createFiberFromCache(pendingProps, mode, lanes, key);
        }
      // eslint-disable-next-line no-fallthrough
      case REACT_TRACING_MARKER_TYPE:
        if (enableTransitionTracing) {
          return createFiberFromTracingMarker(pendingProps, mode, lanes, key);
        }
      // eslint-disable-next-line no-fallthrough
      case REACT_DEBUG_TRACING_MODE_TYPE:
        if (enableDebugTracing) {
          fiberTag = Mode;
          mode |= DebugTracingMode;
          break;
        }
      // eslint-disable-next-line no-fallthrough
      default: {
        if (typeof type === 'object' && type !== null) {
          switch (type.$$typeof) {
            case REACT_PROVIDER_TYPE:
              fiberTag = ContextProvider;
              break getTag;
            case REACT_CONTEXT_TYPE:
              // This is a consumer
              fiberTag = ContextConsumer;
              break getTag;
            case REACT_FORWARD_REF_TYPE:
              fiberTag = ForwardRef;
              if (__DEV__) {
                resolvedType = resolveForwardRefForHotReloading(resolvedType);
              }
              break getTag;
            case REACT_MEMO_TYPE:
              fiberTag = MemoComponent;
              break getTag;
            case REACT_LAZY_TYPE:
              fiberTag = LazyComponent;
              resolvedType = null;
              break getTag;
          }
        }
        let info = '';
        if (__DEV__) {
          if (
            type === undefined ||
            (typeof type === 'object' &&
              type !== null &&
              Object.keys(type).length === 0)
          ) {
            info +=
              ' You likely forgot to export your component from the file ' +
              "it's defined in, or you might have mixed up default and " +
              'named imports.';
          }
          const ownerName = owner ? getComponentNameFromFiber(owner) : null;
          if (ownerName) {
            info += '\n\nCheck the render method of `' + ownerName + '`.';
          }
        }

        throw new Error(
          'Element type is invalid: expected a string (for built-in ' +
            'components) or a class/function (for composite components) ' +
            `but got: ${type == null ? type : typeof type}.${info}`,
        );
      }
    }