Typescript patterns

pickKeys.ts

const extractFromObj = <T, K extends keyof T>(
   obj: T,
   keys: K[]
 ): Pick<T, K> => {
   return keys.reduce((newObj, curr) => {
     newObj[curr] = obj[curr];

     return newObj;
   }, {} as Pick<T, K>);
};
type sProduceConditionsMapper<T> = {
  [K in keyof T]?: string[];
};
const pickObjectKeys = <
  T extends sProduceConditionsMapper<T>,
  K extends keyof T
>(
  obj: T,
  keys: K[]
): { [O in K]: string[] } => {
  return keys.reduce((newObj, curr) => {
    // if (Array.isArray(obj[curr])) {
    newObj[curr] = obj[curr] || [];
    // newObj[curr] = obj[curr];
    // }

    return newObj;
  }, {} as { [O in K]: string[] });


type ProduceConditionsMapper<T> = {
   [K in keyof T]: ((input: T[K]) => void) | Promise<T[K]>;
}