Improve TS typings for filterObject using TS 4.7 Instantiation Expressions

[nelsonni]

Is your feature request related to a problem? Please describe.
The return type for filterObject() is subtly incorrect:

synectic/src/containers/format.ts

Lines 146 to 150 in 68281d0

	export const filterObject = <V, T extends Record<string, V>>(obj: T, filter: string[]): T | Record<string, never> => {
	return Object.entries(flattenObject(obj))
	.filter(([key]) => filter.includes(key))
	.reduce((accumulator, [k, v]) => ({ ...accumulator, [k]: v }), {});
	}

Although the possibility exists for filtering to result in an empty object (i.e. Record<string, never>), this forces us to provide an initialValue in the Array.reduce() which incorrectly allows the TypeScript compiler to infer that all inputs can become {}.

Describe the solution you'd like
To improve the typings, we can change the return type to be the flattened object resulting from flattenObject():

ReturnType<typeof flattenObject<T>>

However, this type definition requires using Instantiation Expressions which will be added in the TypeScript 4.7 release.

Additional context
The use of type arguments for generic functions or generic constructions (i.e. Instantiation Expressions), currently throws errors from @typescript-eslint/eslint-plugin. ehaynes99/typescript-eslint-instantation-expressions includes a minimum reproduction build for these ESLint errors in anticipation of TS 4.7.