Object.entries behaves differently for interfaces and types

Bug Report

When using types, Object.entries returns a union of possible values as value, while a similar interface, it returns any

🔎 Search Terms

Object.entries union any

🕗 Version & Regression Information

This seems to go back at least until TS 4, I didn’t test further.

⏯ Playground Link

Playground link with relevant code

💻 Code

// explicit type has union as value type
{
    type Foo = {
        key: "value",
        anotherKey: number
    }

    let x: Foo = { key: "value", anotherKey: 3 }

    //const entries: [string, number | "value"][]
    const entries = Object.entries(x)
}

// explicit interface has `any` as value type
{
    interface Foo {
        key: "value",
        anotherKey: number
    }

    let x: Foo = { key: "value", anotherKey: 3 }

    //const entries: [string, any][]
    const entries = Object.entries(x)
}

🙁 Actual behavior

Object.entries behaves differently for types and interfaces

🙂 Expected behavior

Object.entries behaves the same for types and interfaces.

I am aware that the general argument is “interfaces could be extended” - but pretty much the same goes for a type here as well, right? Is this an oversight or intended behaviour?

[Josh-Cena]

Object.entries() should really always return any or unknown.

You mean [string, any][]?

[phryneas]

Ah, that’s at least a puzzle piece that explains it.