Comparison with TypeScript erasable enum feature idea

[littledan]

What are the pros and cons of this feature vs microsoft/TypeScript#61414 ?

[andyearnshaw]

Some of the pros are explicitly listed in the README:

An enum declaration provides several advantages over an object literal:

• Closed domain by default — The declaration is non-extensible and enum members would be non-configurable and non-writable.
  ...
• Self-references during definition — Referring to prior enum members of the same enum in the initializer of a subsequent enum member.

It doesn't mention that the [[Prototype]] of enums as part of these proposals is empty, meaning they don't inherit from Object.prototype, another significant benefit.

In TypeScript, as enum would declare the type as readonly but, similar to as const, that doesn't stop non-TypeScript code from modifying the object.

As for cons of this proposal, the only one I can really think of is that it is new syntax and those pros have to overcome the high bar required for new syntax in the language. For me, they do, but I don't think that carries any weight!