Inferring a type from within an interface's properties

Question

I have a memoizer that allows you to transform arguments before comparing, something like so:

function sum(x: number, y: number) { return x + y; }

const memoSum = memo(sum, {
  // receives an array of numbers ([x, y]) and converts to a string (i.e., `${x},${y}`)
  transformArgs: (args) => args.join(','),

  // receives the transformed arguments (strings in this case)
  isEqual(a, b) => a === b
})

Is there a way to write an interface that infers the type of arguments a and b iff transformArgs is provided? Something like:

interface MemoOptions<F extends AnyFunction> {
  transformArgs(args: Parameters<F>): TransformedArgsHereDefaultsToParametersF;
  isEqual(a: TransformedArgsHereDefaultsToParametersF, b: TransformedArgsHereDefaultsToParametersF): boolean;
}

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Edit: Adding TS playground with the answer. Thanks for helping!

Answer 1

Simply add another generic type parameter:

interface MemoOptions<F extends AnyFunction, R> {
    transformArgs(args: Parameters<F>): R;
    isEqual(a: R, b: R): boolean;
}

TS Playground