Object.entries({ a: 42 }) returns [string, unknown][]

[matzkoh]

In the typescript lib, the union type of values simply becomes the new value type.

entries<T>(o: { [s: string]: T } | ArrayLike<T>): [string, T][];

Compared to the above, the implementation of this lib is a bit more complex.

Please let me know if I've missed something.

[uhyo]

Thank you for reporting this, and sorry for late response.

This is actually an “improvement” compared to the original result; see the below example.
better-typescript-lib considers the possibility of existence of properties that do not appear in types.
Actually TypeScript's lib does the same thing for Object.keys (which always returns string[]), but somehow doesn't for Object.entries and Object.values.

Ideally we should have detected an object literal directly passed to Object.entries so that such a consideration isn't needed, but I think this isn't possible with current type system.

type FooObj = {
    foo: number;
}

const obj1 = {
    foo: 123,
    bar: "Hello!"
}

const obj2: FooObj = obj1;

for (const [key, value] of Object.entries(obj2)) {
    // Default TypeScript definition: value is number
    // better-typescript-lib: value is unknown

    console.log(value); // 123 and "hello!" are shown
}