mergeValueKinds() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingEffects.ts lines 2935–2975

function mergeValueKinds(a: ValueKind, b: ValueKind): ValueKind {
  if (a === b) {
    return a;
  } else if (a === ValueKind.MaybeFrozen || b === ValueKind.MaybeFrozen) {
    return ValueKind.MaybeFrozen;
    // after this a and b differ and neither are MaybeFrozen
  } else if (a === ValueKind.Mutable || b === ValueKind.Mutable) {
    if (a === ValueKind.Frozen || b === ValueKind.Frozen) {
      // frozen | mutable
      return ValueKind.MaybeFrozen;
    } else if (a === ValueKind.Context || b === ValueKind.Context) {
      // context | mutable
      return ValueKind.Context;
    } else {
      // mutable | immutable
      return ValueKind.Mutable;
    }
  } else if (a === ValueKind.Context || b === ValueKind.Context) {
    if (a === ValueKind.Frozen || b === ValueKind.Frozen) {
      // frozen | context
      return ValueKind.MaybeFrozen;
    } else {
      // context | immutable
      return ValueKind.Context;
    }
  } else if (a === ValueKind.Frozen || b === ValueKind.Frozen) {
    return ValueKind.Frozen;
  } else if (a === ValueKind.Global || b === ValueKind.Global) {
    return ValueKind.Global;
  } else {
    CompilerError.invariant(
      a === ValueKind.Primitive && b == ValueKind.Primitive,
      {
        reason: `Unexpected value kind in mergeValues()`,
        description: `Found kinds ${a} and ${b}`,
        loc: GeneratedSource,
      },
    );
    return ValueKind.Primitive;
  }
}