mApply

type Null = undefined | null
type MVal<T> = T | Null
type Nullify<T> =  {
    [P in keyof T]: MVal<T[P]>;
};
type MParams<T extends (...args: any) => any> = T extends (...args: infer P) => any ? Nullify<P> : never;

declare function apply<F extends (...args: any) => any>(f:F, ...args: Parameters<F>): ReturnType<F>

declare function mApply<F extends (...args: any) => any>(f:F, ...args: MParams<F>): MVal<ReturnType<F>>

const inc = (a: number):number => a + 1
const sum = (a: number, b:number):number => a + b

const x1 = apply(inc, 3)
const x2 = apply(sum, 3, 4);

const x = mApply(sum, 3, null);
const y = mApply(inc, null);

https://www.typescriptlang.org/v2/en/play?#code/C4TwDgpgBAcgrgGwVAvFOA7AJhAZgSwwiygB8oNEEBYAKFEigFkA1AQwQB4AVAPlSjcysKnQbR4SfLhA9+aKAG86UVVADaABSiEoAawggA9rkEBdAFzN2XblrO8A3HQC+z+uGhNNbAE5sAWwBnHigIAA9gCGwgqAAKADokvwBzIKs2DBAASlR+TJB5QTDI6KxYxOTfNKtCXAhfKE1clHysqAB+ESkZTk1+KyIANwb3OhwAYwQ-aFxMCeB8IwwoNjAwBFkAMRKomPikhNT01ayWtsK43AstgBooQ+OrH38AiCjfEK3ebKsAJXecF8GG4nk43zo4wgUxmUDmGAWSxWAQAgutNuDdmUKo9qicCudTpdrncHlUaswXoEvj8rKwOJwAcAgSCwd9eJDaBNlkFgDoEQI4mxBnAAgAjBq-Sjihp5VZQADUUAAjHRuRheVAgqLBcKKKKJb57mKLNLDVKDbLWvKlWLOerNeFlQI1hsQHFCBN7gBmbJqnl88IAJhd6Pd2oCPvuABZsmMuQGoOEBKiw3EI1H9Ug4-6NXyQCm0W6PQj7pRs+4gA