Enums should have a null prototype

TypeScript Version: 4.0.2

Search Terms:

• enum
• string
• prototype

Code

    const userInput = 'hasOwnProperty' as string

    enum Action {
        create,
        update
    }

    if (userInput in Action) {
      const a: Action = Action[foo as keyof typeof Action]

      console.log(typeof a) // => function
    }

Expected behavior:
Transpiled enums should have a null prototype.

Actual behavior:
Transpiled enums inherit from Object.prototype

Playground Link:
https://www.typescriptlang.org/play?ssl=11&ssc=24&pln=9&pc=29#code/MYewdgzgLgBAZiEMC8MDkALAhhA8gdzAAUAnEABwFMSoBPNAWAChnKwBXAWxgEFgoAluBgBvZjBjASlLFEoAacTHbkAJrMrMAvs2YC4MABS4ARgCtK-AHTkyUEHSpXseQqQrU6V4FgA2vwz5BcHl4RABKcNElUEhYLAAuXn4hMBRk4LAAbQQkHBgAa0paEANHSlKM1IBdXSYJWIgQX0orXxAAc0Nyyqxw7SA

Related Issues:

Start with the linked TypeScript Playground and reproduce the enum lookup using the shown code. Trace the compiler's enum emission path and assess the impact of changing the emitted object's prototype. Done means transpiled enums have a null prototype without breaking existing enum behavior, with regression coverage for the reported case.