how to create an enum-like object with bigint initializers in typescript?

Question

What I would ideally do is:

enum Distance {
    Far: 0n,
    Medium, // 1n
    Close, // 2n
}

function Calculate(length: Distance) {
    // do something here
}

Unfortunately enums do not support bigints yet, so that doesn't work.

I've tried something like:

const Distance = {
    Far: 0n,
    Medium: 1n,
    Close: 2n
}

type Distance = typeof Distance;

function Calculate(length: Distance) {
    const answer = 1n + length;
    // Operator '+' cannot be applied to types 'bigint' and '{ Far: bigint; Medium: bigint; Close: bigint }'
}

But that doesn't seem to work (I can't use it as I would a normal enum).

I know I can just cast the number to a bigint with BigInt() but I'd rather not do that.

How can I create something that functions like an enum because that uses bigints instead of numerals or strings?

Answer 1

Your initial idea of using a constant object instead is good. Your mistake is your type Distance that isn't what you expect:

Your values are bigints, therefore use bigint as type:

const Distance = {
    Far: 0n,
    Medium: 1n,
    Close: 2n
}

type Distance = bigint;

function Calculate(length: Distance) {
    const answer = 1n + length;
}

You'll see that this will work, since both 1n and length will be bigints.