Generating eliminator for given constraint in typescript

constraints.ts

/** If you want to know how to encoding HKTs in typescript, check this: 
    https://gist.github.com/ENvironmentSet/1662a140f99381bc85fd6be51ecdcbb5
    
    Sorry for messy names, this was only PoC.                            **/

export interface HKT {
  param: unknown;
  result: unknown;
}

export type Apply<f extends HKT, x>
  = (f & { param: x })['result'];

export type ElimWithConstraint<constraint extends HKT> = <R>(f: <A>(x: Apply<constraint, A>) => R) => R;
export function makeElimWithConstraint<constraint extends HKT>(): <A>(x: Apply<constraint, A>) => ElimWithConstraint<constraint> {
  return x => f => f(x);
}
  

excludeBottomConstraint.ts

import { HKT, Apply, makeElimForConstraint } from './constraints';

export interface ExcludeBottomConstraint extends HKT {
  result: this['param'] extends undefined | null ?
            never
          : this['param'];
}

export const elimNonBottom = makeElimWithConstraint<ExcludeBottomConstraint>();

idconstraints.ts

import { HKT, Apply, makeElimForConstraint } from './constraints';

interface IdentityConstraint extends HKT {
  result: this['param'];
}

export const elimAny = makeElimWithConstraint<IdentityConstraint>();

truthyconstraints.ts

import { HKT, Apply, makeElimForConstraint } from './constraints';

export interface TruthyConstraint extends HKT {
  result: this['param'] extends undefined | null | 0 | '' | false | typeof NaN ?
            never
          : this['param'];
}

export const elimTruthy = makeElimWithConstraint<TruthyConstraint>();