How to use typescript generic type as an object key

Question

function myFunc<T extends string>(key: T): Record<T, string> {
        return { [key]: 'asdf' };
    }

I get an error:

Type '{ [x: string]: string; }' is not assignable to type 'Record<T, string>'.ts(2322)

How to get rid of the error and enable auto-completion on the returned object?

P.S. Without using return { [key]: 'asdf' } as Record<T, string>

k.tten · Accepted Answer · 2022-10-14 23:38:25Z

2

Move the signature into an overload:

function myFunc<T extends string>(key: T): Record<T, string>;
function myFunc(key: string) {
    return { [key]: 'asdf' };
}

answered Oct 14, 2022 at 23:38

k.tten

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