Types when passing { deep: true } are wrong

[felixfbecker]

The types type the key and value arguments as keys and values of the passed root object, but when passing { deep: true }, my understanding is these could be deeply nested keys and values (i.e. key: string and value: unknown)

[sindresorhus]

I'm not sure exactly what you mean. Would be great if you could submit a failing type test: https://github.com/sindresorhus/map-obj/blob/master/index.test-d.ts (expectError) or also a fix.

[sscotth]

Possible example:

const input = { foo: { bar: 'baz' }, hello: 'world' }

const output = mapObject(
  input,
  (key, value) =>
    // args with `{deep: true}` shouldn't use `keyof`. In this case `keyof input` is `'"foo" | "hello"'`
    // @ts-expect-error
    key === 'bar' ? mapObjectSkip : [key, value],
  { deep: true },
)

expect(output).toStrictEqual({ foo: {}, hello: 'world' })

Without the expect-error:

This condition will always return 'false' since the types '"foo" | "hello"' and '"bar"' have no overlap.

The problem exists for keys and values

map-obj/index.d.ts

Lines 23 to 24 in 5047229

	sourceKey: keyof SourceObjectType,
	sourceValue: SourceObjectType[keyof SourceObjectType],