Use Enum as restricted key type in Typescript

index.ts

enum Foo {
    A = 'a1', B = 'b1', C = 'c1'
}

// use enum value
const finish = (): Partial<{ -readonly [key in Foo]: string }> => {
    return { [Foo.A]: 'hello'}; // or { 'a1': 'hello' }
}

// use enum key
const finish1 = (): Partial<{ -readonly [key in keyof typeof Foo]: string }> => {
    return { A: 'hello'};
}

const result = finish();

result.a1 = 'other value'

console.log(result);